JPS58113928A - Preparation of high aspect ratio flat particulate iodo-silver bromide emulsion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention This invention relates to a method for preparing a silver iodobromide emulsion comprising a dispersion medium and silver iodobromide grains.

(b) Prior Art ■ Silver Iodobromide Grain Radiation-sensitive emulsions used in the photographic field are usually composed of a dispersion of gelatin interbedded with microcrystals (known as grains) of radiation-sensitive halide steel. . Emulsions other than copper iodobromide emulsions have only limited use in camera-sensitive photographic elements.

U.S. Pat. No. 3,320,069 preferably includes 1 to
A gelatin-silver iodobromide emulsion containing 10 moles of iodide is disclosed. The iodobromide steel particles do not consist partly of silver bromide crystals and the rest of the iodobromide crystals. Rather, all of the crystals contain both bromide and iodide, i.e., the amount of copper iodide in silver bromide is less than its solubility limit, i.e., the iodide content is less than about 40 moles (the solubility limit is (depending on the temperature of particle formation), although much lower iodide concentrations are typically employed. Except for special applications, iodide in amounts greater than about 20 molar ratios is rarely used in iodobromide steel. Even very small amounts of iodide, such as thymol 0.005, can provide benefits.

Unless otherwise specified, all silver halogen percentages are based on the steel present in the corresponding emulsion, grain, or grain region. For example, a variety of regular and irregular particle shapes have been observed in halogen fluoride, which is used in the production of black and white photographs in general and in the production of radiographic bonds in particular. Regular particles are often cubic or octahedral. Particles and particles may exhibit roundness due to aging effects.

In addition, in the presence of a strong release agent such as ammonia, the particles can become spherical or thick plate-like near spheres. This is true, for example, in US Pat. No. 3,894.871 and Z@llkman and Levy (
Focal Press, ]964
, pp. 22]-223. Rods and tabular grains are often observed in varying proportions among other grain shapes. This is especially true if the pAg (the reciprocal of the logarithm of the ion concentration) of the emulsion is, for example,
W is observed when it changes during the process of precipitate formation, as seen in the single-jet precipitation method.

Tabular copper bromide grains have been widely studied, but most of them are macro-sized and cannot be used in the photographic field. Tabular grains, which refer to grains with two parallel or substantially unilateral crystal faces that are substantially larger than a single crystal face, have an aspect ratio (i.e., diameter to thickness ratio) of substantially 1: higher than 1. High aspect ratio tabular grain silver bromide emulsions have been studied by Cugnaa and Chateau.The evolution of bromide chain crystal morphology upon physical ripening op silver bromide crystals
"During Physical Resonation" Science, Engineering, Eastman Photography, Volume 33, A
2 (1962), pp. 121-125.

From 1937 to the 1950s, Eastman Kodak manufactured Dusolitized radiographic film products with no-screen X-ray code 5133.
It was sold under the name ``. This product had sulfur sensitized copper bromide emulsion coating layers on opposite major sides of the film support. Since this emulsion was to be exposed to Xls radiation, it was spectrally sensitized. The tabular grains had an average aspect ratio of about 5-7:. The tabular grains accounted for more than 50 squares of the projected area, and the non-tabular grains occupied more than 25 squares of the projected area. While visiting and copying these emulsions,
The emulsion with the highest average aspect ratio has an average tabular grain diameter of 2.5 micrometers and an average tabular grain thickness of 0.36.
It exhibited a micromeander and an average aspect ratio of 7:1. Other replica emulsions are thicker and have larger diameter tabular grains with lower average aspect ratios.

Although tabular grain silver iodobromide emulsions are known in the photographic industry, none are known to exhibit high average ascent density.
fln)r Photographic Emulsion Chemistry, Focal Press, 1966
, pp. 66-72 and Trivslli
) - and Smith, "The influence of silver iodine on the structure of the iodobromide precipitate series," De Photography, Journal, Vol. LXXX, July 1940, pp.
, 285-288. Tripelli and Smith observed a significant reduction in both particle size and aspect ratio with the introduction of iodide. Gutov (Cut
off) "Nucleation and growth rate in precipitation formation of silver halide photographic emulsions", Photographic Sciences and Engineering, vol. 14, vol. 4.1
970. July-August, pp. 248-257 describes silver bromide and silver iodobromide emulsions of the type prepared by single jet precipitation using continuous precipitation techniques. It has been reported.

Techniques for preparing emulsions in which the major portion of the copper halide is present in tabular grain form have been described in recent publications. U.S. Pat. No. 4,063,951 discloses a tabular crystal defined by a -1 ('10) phantom plane and having an American square ratio (based on edge length) of 1.5 to 7:1. The formation of halogenated compounds is disclosed.

These tabular grains have square and rectangular major faces (1(')
n) Characteristics of crystal planes were shown. U.S. Pat. No. 4, +167.
No. 739 discloses that the size of the seed crystals is increased by forming seed crystals, subjecting the halide to Ostwald ripening in the presence of a chloride agent, and controlling pBr (the reciprocal of the logarithm of the bromide ion concentration). The preparation of copper halide emulsions that are predominantly twinned octahedral crystals by completing grain growth without renucleation or Ostwald ripening is described. U.S. Patent No. 4.150.994
No. 4184877 and No. 4184878, British Patent No. 1.570.581 and German Patent Publication No. 2.905.655 and German Patent No. 2,921.07.
No. 7 teaches the formation of flat twinned octahedral halo particles by using a seed crystal with at least 90 moles of iodide. Some of the above references report increased covering power for emulsions and state that the emulsions are useful as both black and white and color camera films. U.S. Patent No. 4.1163.95
No. 1 states that the upper limit of the aspect ratio is 7:1, but the aspect ratio obtained in the example is 2:1.
This aspect ratio of 7:1 seems to be unrealistically high because it is very low. As seen from the repetition of the examples and from the microscopic photographs, the asquite ratio Fi, 7:1 achieved by the teachings of the other references cited above.
It is clear that it is less than Japanese Patent Application Publication No. 14
No. 2.329 (November 6, 1980) is essentially a compilation of the above references, but its use as a seed particle is not limited to silver iodide.

Chat@mu and d@Cugnae, cited above, have reported the preparation of high aspect ratio tabular grain odor emulsions, including the above-mentioned tri4'J (Triv*111 ) and Smith and a number of other patents, but compared with similarly prepared tabular grain iodobromide emulsions. The results show that the thickness of tabular grains is relatively large, the thickness of non-tabular grains is relatively large, and the proportion of non-tabular grains is high.

(e) DISCLOSURE OF THE INVENTION The object of the present invention is to produce a new method consisting of a dispersion medium and silver iodobromide particles by introducing complex salts, bromide salts and iodide salts into a reactor containing at least a part of the dispersion medium. The object of the present invention is to provide a method for preparing a radiation-sensitive silver iodobromide emulsion (the advantages of which will be described in detail later).

A method of preparing high aspect ratio tabular grain silver iodobromide emulsions superior to the present invention comprises introducing a complex salt, a bromide salt and an iodide salt into a reactor containing at least a portion of a dispersion medium. In a method for preparing a radiation-sensitive silver iodobromide emulsion consisting of silver iodobromide grains, the pBr of the dispersion medium in the reactor is adjusted to 0.6 to 1.6 before introducing the iodide salt. , maintain the reactor in a substantially iodide-free state before introducing the complex salt and the bromide salt, and reduce the p in the reactor during the process of introducing the iodide salt.
Br is present in the dispersion medium in the reactor with a thickness of less than 0.3 micrometers and a diameter of 0.03 micrometers.
．． 6 micrometres or more, average aspect ratio 8:
1, and is characterized by producing silver iodobromide grains occupying at least 50 inches of the total projected area of the silver iodobromide grains.

Term "high aspect ratio" used regarding silver halogen emulsions
In this specification, silver halide grains having a thickness of less than 0.3 micrometers, a diameter of at least 0.6 micrometers, and an average aspect ratio of greater than 8:1 are defined as the total projected area of the I-halogenated chain grains. Refers to at least 50 cm of

Preferred high aspect ratio tabular grain silver rhodanide emulsions have a thickness of less than 0.3 micrometers (more preferably less than 0.2 micrometers), a diameter of at least 0.
．． 6'F micrometers, halogen finished silver grains having an average aspect ratio of at least 12:1 (particularly preferably at least 2n:1). Extremely high average aspect ratios (100:] or sometimes Vi200:] or higher) can also be made from PT. The maximum aspect ratio is only limited by the maximum useful particle diameter, which can be as large as 30 micrometers. In a preferred embodiment of the present invention, the silver iodobromide grains satisfying the above-mentioned thickness, diameter, and aspect ratio are at least 70 inches of the total projected area of the silver iodobromide grains;
Particularly preferably, it occupies at least 90 inches.

The thinner the thickness of the tabular grains that make up a given percentage of the projected area, the higher the average aspect ratio of the emulsion. Usually the average thickness of the tabular grains is at least 0.03 micrometers, preferably at least 0.05 micrometers (although depending on the field the thickness of the tabular grains can be increased). To obtain high aspect ratios without unduly increasing grain diameter, the average tabular grain thickness of the emulsions of this invention will typically be less than 0.3 micrometers.

The above-described grain characteristics of silver iodobromide emulsions can be readily determined by techniques well known in the art.

As used herein, the term "aspect ratio" refers to the ratio f of diameter to thickness of a particle. The "diameter" of a grain refers to the diameter of a circle having an area equal to the projected area of the grain when the emulsion is observed under a microscope or an electron microscope. The thickness and diameter of each grain can be determined from a shaded electron micrograph of an emulsion sample, and the thickness is 0.3 mm.
Tabular grains less than a micrometer and having diameter bundles of at least 0.6 micrometers can be identified.

In this way you can measure the diameter and thickness respectively.

and average the aspect ratio of all grains in the sample that satisfy the criteria of a thickness of less than 0.3 micrometers and a diameter bundle of at least 0.6 micrometers. can be used to obtain the average aspect ratio. As is clear from this, the average aspect ratio is the average of the American aspect ratios of individual tabular grains. In practice, the average thickness and average diameter of tabular grains, usually having a thickness of less than 0.3 micrometers and a diameter bundle of at least 0.6 micrometers, are determined and the ratio of these two average values is calculated to calculate the average It is easy to find the aspect ratio. The average aspect ratio can be determined by taking the average value of the individual aspect ratios, or by calculating it from the average values of thickness and diameter, as long as it is within the allowable range of particle measurements. There is virtually no difference in aspect ratio.

Integrate the projected area of the tabular silver iodobromide grains that satisfy the thickness and diameter criteria, separately integrate the projected surface area of the remaining silver iodobromide grains in the microscopic photograph, and then integrate these two. From the values, the percentage of the total projected surface area of the silver iodobromide grains occupied by tabular grains satisfying the thickness and diameter criteria can be calculated.

Standard tabular grains less than 0.3 micrometers in thickness were selected in the above determinations to distinguish them from thicker tabular grains with inferior photographic properties. The standard particles were chosen to have a diameter of at least 0.6 micrometers. This is because, at smaller diameters, tabular grains and non-tabular grains cannot always be distinguished in micrographs. The term ``projection area'' which is widely used in the industry includes, for example, James (Jan@m) and Higgins (Hlgglns) r Fundamentals of Photographic Theory (-).
Fundamentals 1 (Photographic Theory), Morgan & Morgan, New York,
See P., 15 (1948).

The first line in the margin below is an example of a micrograph of an emulsion produced vIi by the method of the present invention, showing the presence of various grains. Grain 101 is a tabular grain satisfying the above-mentioned thickness and diameter criteria. It is. Most of the grains in FIG. 1 are tabular grains that meet the above thickness and diameter criteria. The average aspect ratio of these particles is 18:l. In this photomicrograph, some particles that do not satisfy the above thickness and diameter can be seen. For example, grain 103 is a non-tabular grain.

The thickness of this particle is greater than 0.3 micrometers.

Particles 105 are fine particles that do not meet the diameter criteria.

Particle 107 is a tabular grain that satisfies the diameter criterion,
The thickness is too large to meet the above criteria. Depending on the emulsion preparation conditions, in addition to the desired tabular, bound silver bromide grains satisfying the above thickness and diameter criteria, large nontabular grains, fine grains, or thick tabular grains may be used, as detailed below. There may be a second group of particles consisting of . Sometimes non-tabular grains such as rods may also be present. Although a greater number of tabular grains satisfying the thickness and diameter criteria described above is generally desirable, the presence of a second group of grains in emulsions or having a high aspect ratio as described above is acceptable. do not have.

High aspect ratio tabular grain silver iodobromide emulsions can be prepared by the precipitation process of the present invention as described below. A dispersion medium is placed in a commonly used reactor for producing silver rognide precipitate, which is equipped with a stirring mechanism. Usually the amount of dispersion medium introduced into the reactor in the initial stage is at least about 1031% of the amount of dispersion medium present in the silver iodobromide emulsion in the final grain precipitation step, preferably from 20 to 1%. It is. As taught in Belgian Patent No. 886,645 (corresponding to French Patent No. 2.471,620),
Since the dispersion medium can be removed from the reactor by ultrafiltration during the silver iodobromide particle precipitation formation process, the IF'i of the dispersion medium initially present in the reactor is removed from the reactor during the final particle precipitation formation stage. It can be equal to or even more than the amount of silver iodobromide present in the emulsion. The dispersion medium initially introduced into the reactor is water or a dispersion of a deflocculant in water, and this dispersion medium is optionally combined with other components such as one or more silver halide ripening agents. and/or blending with a metal dog agent which will be detailed later. If the peptizer is initially present, its concentration is preferably at least 10%, and preferably at least 20%, of the total amount of peptizer present in the final stage of silver iodobromide precipitation. Additional dispersion medium is added into the reactor along with the silver and halide salts, but
This can be introduced from a separate jet. In general, the proportion of dispersion medium is adjusted after completion of the rognide salt process, especially in order to increase the proportion of peptizer.

A small proportion, typically less than 101 quantities, of the bromide salt used to form the silver iodobromide grains is initially present in the reactor to control the bromide ion concentration in the dispersion at the onset of silver iodobromide precipitation formation. . Further, the dispersion medium in the reaction vessel does not initially contain iodide ions. This is because the presence of iodide ions before the simultaneous addition of silver and bromide salt tends to produce thick non-tabular grains. [Free of iodide ions] as used herein with respect to the contents of the reactor means that there is insufficient K to form a precipitate as a separate silver iodide phase in comparison with bromide ions. The total iodide concentration in the reactor into which the silver salt is introduced is preferably maintained at less than 0.5 mole of the iodide ion concentration. If the pBr of the dispersion medium is initially too high, the tabular silver iodobromide grains produced will be relatively thick and have a low aspect ratio.

The pBr in the reactor may initially be 1.6 or less, preferably less than 1.5 KIN. On the other hand, pB
If r is too low, non-tabular silver iodobromide grains are likely to be produced.

Therefore, pBr't in the reactor can be maintained at -0.6 or higher, preferably above 1.1. As used herein, pBr is defined as the negative logarithm of the bromide ion concentration. voice, pcz, pt, and pA
g are similarly defined for hydrogen, chloride, iodide and silver ion concentrations, respectively.

During precipitation, silver, bromide, and iodide salts are added to the reactor according to techniques well known for precipitation of silver iodobromide particles. Usually, an aqueous solution of a soluble silver salt, such as nitrate, is introduced into the reactor at the same time as the bromide and iodide salts are introduced. Bromide and iodide salts also typically contain one or more soluble ammonium, alkali metal (e.g.
sodium or potassium) or alkaline earth metals (
For example, it is introduced as an aqueous salt solution, such as an aqueous solution of a magnesium or calcium halide salt.

The silver salt is introduced into the reactor separately from the iodide salt, at least initially. The iodide and bromide salts may be added to the reactor separately or as a mixture.

Introducing the complex salt into the reactor initiates the particle nucleation step. Continuing with the introduction of scissors, bromide and iodide salts,
A population of grain nuclei is formed which serves as a site for precipitation of silver bromide and silver iodide.

The precipitation of silver bromide and silver iodide onto the existing grain nuclei constitutes the grain growth stage. The aspect ratio of tabular grains formed in accordance with the present invention is less affected by iodide and bromide concentrations during the growth stage as compared to the nucleation stage. Therefore, the permissible range of pBr in the stage of simultaneous introduction of silver, bromide and iodide salts during the growth stage is set at 0.6 or more, preferably in the range of about 0.6 to 2.2, more preferably about 0. It can be increased to a range of .8 to about 1.6.

Increasing the tolerance range for pBr by about 0.8 to about 1.6 reduces grain nucleation substantially during the introduction of silver, bromide, and iodide salts, such as when preparing highly polydisperse emulsions. This is particularly effective when sustained at a certain speed. Increasing the pjJr value by more than 2.2 during the tabular grain growth stage increases the thickness of the resulting grains, but is often acceptable as it still yields grains with average aspect ratios greater than 8:1. I can do it.

Instead of introducing the silver, bromide, and iodide salts as an aqueous solution, the silver, bromide, and iodide salts were initially grown in the form of fine silver particles suspended in a dispersion medium. It can be introduced with

The particle size of 111 is such that when introduced into the reactor, it readily undergoes Ostwald ripening over the larger particle nuclei that may be present.10 The maximum useful particle size depends on the conditions within the reactor, i.e., temperature and It will depend on the presence or absence of solubilizing and ripening agents. Silver bromide, silver iodide and/or silver iodobromide particles can be introduced. Since bromide and/or iodide precipitate in preference to chloride, silver bromochloride and silver iodobromochloride particles can be used. It is desirable that the copper oxide particles be very fine, for example, with an average diameter of less than 0.1 micrometers. Provided that the above pBr conditions are satisfied, silver,
The concentrations and rates of introduction of bromide and iodide salts may be similar to those conventionally used. It is desirable to introduce silver fluoride and rognide salts at a concentration of 0.1 to 5 moles per liter, but a wider concentration range than conventionally used, e.g., per liter, is preferred. A range from 90.01 moles to saturation can be employed. A particularly preferred precipitation technique is to increase the rate of introduction of silver and nolognide salts during the run to reduce precipitation time. The rate of introduction of the silver and... rhodanide salts can be increased by increasing the rate of introduction of the dispersion medium and the silver and... rhodanide salts or by increasing the rate of introduction of the silver and... rhodanide salts in the dispersion medium introduced Although it is desirable to increase the rate of silver and halide salt introduction, U.S. Pat.
, 650,757, 3.672,900, 4.242,445, German Patent Application No. 2,10
No. 7,118, European Patent Application No. 80,102.2
No. 42 and Wei (9)・y) “Growth mechanism of AgBr crystals in gelatin solution (-/'-Loos Mechanism Osci AgBr Crystals in r Latin・
J7 Autograph Science and Engineering, Volume 21 AI, January-February 1977.

It is particularly desirable to keep the introduction rate below a threshold value where the formation of new particle nuclei is likely to occur (i.e. to avoid re-nucleation) as taught in 9.14 et seq. Approximately 3 (1
It is possible to prepare emulsions with coefficients of variation of less than or equal to

The coefficient of variation used here means the standard deviation of particle diameter divided by the average particle diameter, which is 100 times the fc salary. By intentionally carrying out re-nucleation during the growth stage of precipitation, polydisperse emulsions with substantially higher seismic coefficients can, of course, be prepared.

The iodide concentration in the silver iodobromide emulsion obtained by the method of the invention can be controlled by introducing iodide salts. Any commonly used iodide concentration can be employed. Even a negligible amount of iodide, e.g. 0.05
It is recognized that even values as low as molti are useful. The iodobromide emulsion in a preferred form contains at least about 0.1 mole of iodide. Silver iodide up to the solubility limit in silver bromide at the grain formation temperature can be incorporated into tabular silver iodobromide grains. Therefore, at a precipitation temperature of 90° C., silver iodide can be present in the semi-platelet silver iodobromide grains at a concentration of about 40 mol/min. The actual precipitation temperature is t1! .

The temperature can be lowered to about room temperature, for example, about 30°C. Generally, it is desirable to form a precipitate in a temperature range of 40 to 80°C. Desirable for most photographic applications. The best iodide concentration is up to about 15 moles.

Maintaining the relative proportions of iodide and bromide salts introduced into the reactor during the precipitation process at a constant ratio to form a substantially uniform miramide globule in the tabular silver iodobromide grains. The above relative proportions can also be changed to provide different photographic effects. High iodide 7
Sensitivity-granularity advantages can be obtained by selectively locating within the vectometry tabular grains.

These preferred high aspect ratio tabular grains have first and second opposing substantially parallel major faces and a central region extending between the two major faces, and have an iodide content in the central region of The iodide-containing lid is characterized by a lower iodide content in at least one laterally displaceable region extending between the two major surfaces. In one preferred form, the laterally displaced region is laterally circumferentially annular;
It is an area. The central region is usually the part of the particle that is first formed during the precipitation process. However, in a variant, the central region can be allowed to form as precipitate formation progresses. For example, in some cases the line center region may have an annular configuration surrounding a pre-precipitated high iodide content region.

The central region can consist essentially of silver bromide or silver iodobromide. The central region preferably has less than 5 molt.
(preferably less than 3 moles) of iodide, this iodide content being at least 41 moles compared to the laterally displaced area.

The iodide content in the region displaced in the direction of lateral force is up to the saturation limit of the iodide chains in the silver iodide crystal lattice at the precipitation temperature, that is, up to about 40 mol% at the precipitation temperature of 90°C. It can be changed within the range. The laterally displaced region preferably contains about 6 to 20 moles of iodide.

The proportion of high-7 aspect ratio tabular grains that form in the central region depends on many factors, such as grain thickness and aspect ratio;
The iodide concentration in the lateral loading area can vary depending on the developer and additive mix, and the final photographic application. The proportion of high aspect ratio tabular grains formed in the central region can be routinely ascertained. Depending on various other factors previously mentioned, the high aspect ratio tabular grain content of the center region can vary from about 1 to 99% by weight. For most applications, preferred grain thicknesses, aspect ratios, progressively varying iodide concentrations, and laterally displaced regions on the circumference are preferred.
The central area is about 2-50%, preferably about 4-15%.
It is desirable to include high aspect ratio tabular grains of . On the other hand, if the iodide concentration changes rapidly between the central region and the laterally displaced regions, the central region will be approximately 75-97
% tabular grains.

Unique iodide configurations can be achieved simply by increasing the proportion of iodide present during growth of high aspect ratio tabular grains. In the field of photography
As is well known, during the growth process of tabular grains - precipitation of silver rodanide occurs primarily at the edges of the grains, if not at the edges.

If the precipitation conditions are appropriately selected, the increase in the thickness of the tabular grains at the nucleation edge will be negligible, if at all. By suddenly changing the concentration of iodide present in the particle precipitation process, the iodide concentration in the region can be rapidly increased compared to the central region by displacing one or more lateral directions. can. In some cases, the area that can be displaced laterally looks like a castle. Alternatively, the iodide concentration can be gradually increased to form a smooth gradient in the annular region at Kf laterally from the central region. Although usually not preferred, it is possible to reduce the iodide concentration in the outermost portions of the tabular grains.

The extension of the central region between the opposite major faces of the tabular grains is an essential feature of the emulsions obtained (by the process of the invention). The iodide concentration in the central region may not be uniform. For example, the iodide concentration can be, and typically is, increased near the major faces of the tabular grains. Therefore, the iodide concentrations in the central and laterally displaced regions of the tabular grains are found to be approximately the same as the average iodide concentration within these regions. The central region and laterally displaced regions in the major faces may exhibit the same surface iodide concentration, but with a thickness of less than 0.035 micrometers, measured in a direction perpendicular to the major faces of the high aspect ratio tabular grains, such as It is desirable that the central region and the laterally displaced regions have a difference in iodide content, preferably less than 0.025 micrometers, in iodide content.

Modifying compounds can be present during the silver iodobromide precipitation process. Such compounds may be initially present in the reactor or may be added along with one or more salts in accordance with conventional methods. U.S. Pat. No. 1', 195,432.

No. 1,951,933, No. 2,448,060, No. 2.628,167, No. 2,950,972, No. 3
．． No. 488,709: No. 3,737,313, No. 3.
No. 772.031 and No. 4.269,927 and Research Disclosure, Vol. 134, 1975, 6
Mon, Copper as described in item 13452! Thallium - lead, bismuth, cadmium, zinc.

Intermediate chalcogenos (i.e. sulfur, selenium and tellurium).

Modifying compounds, such as compounds of gold and Group I noble metals, can be present during the silver halide precipitation process. Research Disclosure and its predecessor, the Groduct Licensing Index, are based in the UK,
PO9-IEF, Hangshire.

It is a publication of Burband, Homewell and Industrial Opportunities Limited. Moiset et al., Journal of Photographic Science, vol. 25.

1977, PP, 19-27,
, /-shaped grain emulsions can be sensitized by internal reduction during the precipitation formation process.

The respective silver groups and halide salts are described in U.S. Pat.
, s 21,0 Oi No. 3,031,304 and Claes (C1a@s) et al., 7 Otographies Correspondents, i 028. io issue.

1967, P, 162, using a distribution device or using gravimetric feed to adjust the distribution rate and adjust the pH, pBy and /''!! or pAg of the reactor contents. 1 U.S. Pat. No. 2,996,287 to rapidly distribute the reactants into the reactor.
No. 13,342,605, No. 3,415,650, No. 3,785,777, No. 4,147,551
No. and m4. xrl, zz4, English and research
A specially constructed mixing device as described in Disclosure, Volume 166, February 1978, Item 16662 may be used.

In the preparation of tabular grain silver iodobromide emulsions, the dispersion medium is initially placed in the reactor. In a preferred form, the dispersion medium consists of an aqueous dispersion of a peptizer.

Peptizer concentrations of from 0.2 to about 1 O based on the total weight of the emulsion components in the reactor can be employed.

Maintaining the peptizer l111 degree in the reactor below about 6% based on total weight before and during production of the silver halide, and adding emulsion vehicle afterwards for optimum coating properties. Therefore, it is a common practice to adjust the emulsion vehicle concentration to a high concentration. The first formed emulsion has silver halide moles, +about 5 to
50g of peptizer can be included, preferably about 10-30g. Additional vehicle may be added later, thereby reducing its concentration to 100 molar silver halide.
It is possible to increase the K value to as high as 0 g. Preferably the vehicle concentration in the final emulsion is greater than 50 grams per mole of silver halide.

Preferably, the vehicle accounts for about 30-70% by weight of the emulsion layer during coating and drying during the fabrication of photographic elements.

The vehicle (including both binder and peptizer) is -
- Can be selected from those commonly used in the preparation of silver rognide emulsions. Preferred deflocculants are hydrophilic colloids, which can be used alone or in combination with hydrophobic substances. Suitable hydrophilic vehicles include proteins, protein derivatives, cellulose derivatives such as cellulose esters, gelatin such as alkali-processed gelatin (cow bone or leather gelatin) or acid-processed gelatin (pig skin gelatin). , such as gelatin derivatives such as acetylated gelatin and phthalated gelatin. These and other vehicles and vehicle spreading agents are listed in Research Disclosure,
Volume 176, December 1978, Item 17643. Described in Sexy Expansion ■.

Get Rinshita margin. Grain ripening preferably occurs in a reactor at least during the silver iodobromide grain production process. Known copper halide solvents are useful in promoting ripening. For example, it is known to have an excess of bromide ion present in the reactor to promote ripening. It is therefore clear that ripening can be accelerated simply by introducing a bromide salt solution into the reactor. Other ripening agents can be used, and these ripening agents can be incorporated in their entirety into the dispersion medium in the reactor prior to the addition of the silver and halide salts, or The above halide salts, silver salts, or peptizers can also be added and introduced into the reactor. As a further variant, the ripening agent can also be introduced independently at the halide salt and silver salt addition stages. Although ammonia is a known ripening agent, it is not preferred as a ripening agent for use in the silver iodobromide emulsions of this invention to achieve the highest attainable speed-grain relationship. Preferred emulsions according to the present invention are non-ammoniac spanning neutral emulsions.

Preferred ripening agents include sulfur. Thiocyanate salts can be used, such as alkali metal thiocyanate salts, especially sodium and potassium thiocyanate salts, and ammonium thiocyanate salts. Although the introductory diet of thiocyanate salt may be in conventional amounts, preferred concentrations are generally from about 0.1 to 20.0% per mole of silver chloride.
The range is 9.

The use of thiocyanate ripening agents is described in U.S. Patent No. 2.2.
22,264, No. 2,448,534, and No. 3,320,069. Or U.S. Pat. No. 3,271,157, U.S. Pat. No. 3.574,62
Conventional thioether ripening agents such as those described in No. 8 and No. 3,737,313 can also be used.

The high aspect ratio tabular grain iodobromide chain emulsions obtained by the process of this invention are preferably washed to remove soluble salts. Removal of soluble salts is described in Research Disclosure', Volume 176, December 1978, Item 1764.
3. Sexy, νnK to be collected, tilted, filtered,
and/or by well-known techniques such as cryo-sedimentation and leaching. Prior to use, emulsions with or without sensitizers were prepared in Research Disclosure, Vol. 101, September 1972.

Cough, dry and store as listed in item 10152. In the present invention, increasing the sharpness of tabular grains,
In order to avoid a reduction in aspect ratio and/or an excessive increase in diameter, it is particularly advantageous to wash the tabular silver iodobromide grains at the end of their ripening after precipitation has been completed.

Once formed, the high aspect ratio tabular grain emulsion can be sheathed into a core-sheath emulsion by techniques well known in the art. Any photographically useful silver salt can be used to form a sheath in the high aspect ratio tabular grain emulsions made by the method of this invention. Techniques for forming silver salt sheaths are described in U.S. Pat. Nos. 3,367.778 and 3,2.
No. 06.313, No. 3.317,322, No. 3,
No. 917,485 and No. 4,184,878.

Conventional sheathing techniques are not advantageous for the formation of high aspect ratio tabular grains, as further sheathing reduces the average aspect ratio of the emulsion. If conditions exist in the reactor that favor the production of tabular grains during the sheath formation process,
Sheath formation occurs preferentially at the outer edge of the grain, and as a result, the aspect ratio does not necessarily decrease. If the above-mentioned tabular silver halide grain preparation method is followed, tabular grains that satisfy the thickness and diameter criteria for the aspect ratio are obtained. At least 4 of the total projected area of all silver halide grains
Although it is possible to prepare high aspect ratio tabular grain emulsions of up to 70, it is recognized that greater benefits are achieved by increasing the proportion of such tabular grains. It is desirable that the tabular silver halide grains satisfying the thickness and diameter criteria occupy at least 7016 (more preferably at least 4901) of the total projected area.
Although the presence of small amounts of non-tabular grains is completely acceptable in many photographic applications and still provides the benefits of tabular grains, the proportion of tabular grains can be increased. Large tabular silver halide grains can be separated from small non-tabular grains in the grain mixture using conventional separation techniques such as centrifugation or hydrocyclones.

Separation by hydrocyclone is based on U.S. Patent No. 3,326.
, No. 641.

High aspect ratio tabular grain silver halide emulsions are chemically sensitized. Chemical sensitization td T, H, Jamas.

It can be carried out using activated gelatin as described in The Theory of the Photographic Process, 4th Edition, Macmillan, 1977, pp. 6-76, and also in Research Disclosure, Vol. 120, 1
April 974, Item 12008. Research Disclosure.

Volume 134, June 1975, Item 13452° U.S. Patent No. 1,623°499;
No. 2,399,083, No. 2,642,3
No. 61, No. 3,297,447, No. 3,297,
No. 446.

Same No. 3,772,031, Same No. 3,761,267.

Same No. 3,857,711, Same No. 3,565,633.

3.901,714 and 3.904,41
pAg 5-5 as described in British Patent Nos. 1,315,755 and 1,396,696.
10, using sulfur, selenium, tellurium, gold, platinum, palladium, iridium, mu, osmium, rhodium, rhenium or phosphorus sensitizers or combinations of these sensitizers at pH 5-8 and temperature 30-80°C. 7. Chemical increase # is optimally performed in accordance with U.S. Patent No. 2,
642,361, and in the presence of thiocyanate compounds as described in U.S. Pat.
No. 57 is carried out in the presence of sulfur-containing compounds of the type described in No. 57. Finishing (Chemical Sensitization) Can be chemically sensitized in the presence of modifiers. The finishes used include modifiers that prevent fogging during chemical sensitization, such as azaindenes, azapyridazines, azopyrimidines, benzothiazolium salts, and sensitizers with one or more heterocyclic nuclei. Compounds known to suppress and increase sensitivity are used. Examples of finish modifiers, U.S. Pat. No. 2,131,
No. 038, No. 3,411,914, No. 3,554
, No. 757, No. 3,565,631 and No. 13,
9o1, 7x44! .

Canadian Patent No. 778.723 and Duffin
fin), Photographic Emulsion Chemistry, Focal Press (1966).

New York, pp. 138-143. In addition to or in place of chemical sensitization,
No. 891,446 and No. 3,984,249, reduction sensitization can be performed, for example, using hydrogen, and U.S. Pat. No. 2,983,609, Oftedall et al. , Research Disclosure, vol. 136.

August 1975, Item 13654. U.S. Patent No. 2,
No. 518,698, No. 2,739,060, No. 2
．． 743.182, 2,743.18°3, 3,026,20°3 and 3,361,56
4, using reducing agents such as stannous chloride, thiourea dioxide, polyamines, and amine gellans, or by sensitizing with low pAg (eg, less than 5). US Pat. No. 3,917,485 In addition to chemical sensitization, the high-aquid ratio tabular grain silver iodobromide emulsions obtained by the process of this invention are spectrally sensitized in many applications. Spectral sensitizing dyes can be used that exhibit absorption maxima in the blue and minus blue (ie, green and /l or red) portions of the visible spectrum. In addition, Hiro in special application areas,
Using spectral sensitizing dyes, spectral sensitization beyond the visible spectrum can be demonstrated.For example, it is possible to use infrared absorption spectral sensitization.

Silver heronide emulsions can be spectrally sensitized using various dyes. Dyes used include cyanines, merocyanines, complex cyanines and 6-cyanines (i.e. tri-, tetra- and poly-myanines and merocyanines), oxonol, hemioxonol, styryl, merostyryl and 4-limethine, including streptocyanine. Contains dye.

Cyanine spectral sensitizing dyes include quinolinium, pyridinium, inquinolinium, 3H-indolium, and benz[
・]Indolium, oxacillium, oxazolinium, thiazolium, thiazolinium, selenacillium, selenazolinicum, imidazolium, imidazolinium,
From benzoxacillinium, dithiazolium, benzoselenazolium, one-day dazolicum, naphthoxazolium, natthiazolicum, naphthoxazolium, dihydronaphthothiazolicum, biryllium and imidazozeradinium quaternary salts It includes two basic heterocyclic nuclei connected by a methine linkage, as shown in FIG.

Merocyanine spectral sensitizing dyes include barbituric acid, 2-
Thiobarbic acid, lomenine, totantoin, 2-
thiohydantoin, 4-thiohydantoin, 2-pyrazolin-5-o/, 2-isousazolin-5-one, inmen-1,3-dioo, ., nkuji). "t't:y
-i, 3-'Lyky, I, +3□=nidioxane-4,6-dione pyrazoline-3,5-dione, inthane-2,4-dione, alkylsulfonylacetonitrile, malononitrile, inquinolin-4-one and The acidic nucleus derived from chroman-2,4-dione and the cyanine dye-type basic heterocyclic nucleus are bonded by a methine bond and contain a companion.

Two or more spectral sensitizing dyes can be used for tti.

Dyes are known that have a maximum sensitivity of 1 degree to wavelengths throughout the visible spectrum and have a wide variety of spectral sensitivity curve shapes.The selection and relative proportions of dyes are desired for sensitization. Depending on the region of the spectrum and the shape of the spectral sensitivity curves desired, dye lines with overlapping spectral sensitivity curves are often combined with sensitivities at each wavelength in the overlapping region approximately equal to the sum of the sensitivities of the individual dyes. Thus, by using a combination of dyes with different maximum sensitivities, a spectral sensitivity curve with a maximum intermediate between the maximum sensitivities of the individual dyes can be obtained.

Combinations of spectral sensitizing dyes can be used, thereby producing supersensitization, that is, greater sensitization in a given spectral region than when one of the spectral sensitizing dyes is used alone at any concentration. In addition, large spectral sensitization is achieved due to the acidic effect of these spectral sensitizing dyes. Supersensitization involves the addition of spectral sensitizing dyes and other additives such as stabilizers and anticapri agents, development accelerators or inhibitors, coating aids, fluorescent brighteners and antistatic agents.9
Achieved through selected combinations. Several mechanisms and compounds that may be responsible for hypersensitization are discussed in Gilman's Review of the 117A Mechanism (Review of the M@ahanj).
sms of8apers@n5itiation)
J Photographic Science Anr. Engineering/
//Nearing, Volume 18.

1974, pp. 418-430-c i, b
.

Spectral sensitizing dyes affect the emulsion in other ways. In addition, the spectral sensitizing dye is disclosed in U.S. Patent No. 2,131,038.
No. 3,930,860, it acts as a ron acceptor or electron acceptor, an antifoggant or stabilizer, a development accelerator or inhibitor.

Among the spectral sensitizers useful for sensitizing silver iodobromide emulsions are Research Disclosure, Vol. 176, 1978.
December, Item 17643. There are things described in Nanakushi and 7rin.

An optimum amount (i.e., an amount sufficient to achieve the maximum photographic speed achievable from the grains of at least 460 mm under the exposure conditions) of a high aspect ratio tabular grain silver iodobromide emulsion. The amount of dye used that is desired to be absorbed onto the particle surface will vary based on the particular dye or combination of dyes used and the size and aspect ratio of the particles; optimum spectral sensitization will be achieved. surface sensitization achieved when organic dyes are incorporated in a monolayer coverage corresponding to about 25 to 100 inches or more of the total available surface area of the silver ronide grains. This is known in the art, e.g.
(W@s t), etc. [Adsorption of sensitizing dyes in photographic emulsions (De adsorption scenes of sensitizing mazes in 7 otographic emulsions)”, Digital O!・Physical chemistry,
Volume 56.

p, 1065 e 1952 Varnish 4th (Sp・ne
@) et al., “Desensitizing Dye (Desensitizing Maze)”, Journal of Physical and Chemical Chemistry, 5
Volume 6, No. 6, June 1948 = Ri p-1090-110
3: and US Pat. No. 3,979,213. The optimum dye density level is Maze (M@@I), Theory of Photography, 7”D
pp-1067-1069 (1942゜Macmillan)
It can be selected by the method taught by K. In emulsion layers in which blue light exposure is to be recorded, the natural blue sensitivity of silver bromide is generally exploited, but particular advantages can be obtained by the use of complementary spectral sensitizers.

Spectral sensitization can be performed at any stage of emulsion preparation known to be useful. Most commonly, spectral sensitization is performed subsequent to completion of chemical sensitization. However, spectral sensitization can be performed simultaneously with chemical sensitization, as taught in U.S. Pat. It is also possible to start the spectral sensitization before the completion of silver halide grain precipitate formation. As taught in U.S. Pat. No. 4,225,666, the spectral sensitizing dyes are introduced separately into the emulsion, i.e.
A portion of the spectral sensitizing dye is present prior to chemical sensitization,
The remainder can be introduced after chemical sensitization. Unlike U.S. Pat. No. 4,225,666, a spectral sensitizing dye can be added to the emulsion after the iron halide is precipitated. Sensitization can be enhanced by PAW modulation including circulation during chemical and/or spectral sensitization. Examples of e pAg modulation include Research Disclosure;
1811 May 1979, Item 18155.

High aspect ratio tabular grain silver iodomonide emulsions contain low aspect ratio tabular grains when chemically sensitized and spectral sensitized, and /l or the highest sensitivity-granularity known to date. In one preferred form, the splitting photosensitizer is added to the present invention prior to chemical sensitization. It can be incorporated into such emulsions. Also, in some cases similar results have been achieved by introducing other adsorbable substances, such as finishing modifiers, into the emulsion prior to chemical sensitization.

Independently of the pre-incorporation of the adsorbable substance, about 2×10' to 2 mol. Other ripening agents can also be used during the chemical sensitization process, preferably using thiocyanates.

In combination with either or both of the above-mentioned techniques, and independently of these, as a third technique, silver and/or silver present immediately before or during chemical sensitization can be It is desirable to adjust the concentration of halide salts, silver osyanate, silver phosphate,
Silver salts such as silver carbonate and the like as well as soluble silver salts such as silver acetate, silver trifluoroacetate and silver nitrate can be introduced.

Fine octaa that can undergo Ostwald ripening on the surface of tabular grains
)yk silver chloride (i.e., silver bromide, silver chloride and/or silver chloride) particles can be introduced.

For example, Ridgeman emulsions can be introduced during the chemical sensitization process. Additionally, chemical sensitization of high aspect ratio tabular grain emulsions to spectrally sensitize can be accomplished at two or more predetermined discrete locations on the tabular grains. Chemical sensitization can occur on different crystal surfaces of the tabular grains by being preferentially adsorbed on the crystal surfaces forming the major surfaces of the tabular grains.

Preferred chemical sensitizers for obtaining the highest achievable sensitivity-granularity relationship are gold and sulfur sensitizers, gold and selenium sensitizers, and gold, sulfur and selenium sensitizers. In a preferred embodiment, the high aspect, single tabular grain silver bromide emulsion contains a silver bromide emulsion containing sulfur and/or an intermediate chalcodane such as selenium (which may or may not be detectable) and detectable gold. Although emulsions usually contain detectable amounts of thiocyanate, the concentration of thiocyanate in the final emulsion can be significantly reduced by known emulsion washing techniques. In the various preferred embodiments described above, the tabular silver bromide grains are coated with another silver salt, such as silver thiocyanate, on their surface, or with another silver halide containing different silver halide contents. For example, silver chloride may contain silver bromide.

Sub-detectable amounts of other silver salts may also be present.

Although it is not necessary to achieve all the advantages, it is desirable that the emulsions obtained by the process of the invention be optimally chemically and spectrally sensitized, which means that under possible use and processing conditions the sensitized spectra This means that it is desirable to achieve a sensitivity equivalent to at least 60 degrees of the maximum Log sensitivity achieved from those particles in the region 2.
, where Log sensitivity means 100100 (1-14; in this formula, E is the exposure amount expressed in meters-cantreux seconds at Capri J-0, IC) density.

Once the silver halide grains in the emulsion layer have been characterized,
Whether the emulsion layers of a product are substantially optimally chemically and spectrally sensitized relative to comparable products from other manufacturers can be determined by further product analysis and performance evaluation. .

Although the silver halide emulsion is sufficiently chemically or spectrally sensitized to achieve the sharpness targeted by the present invention, it is not important whether such sensitization is insufficient.

Margins Below Once high aspect ratio tabular grain emulsions have been produced by the precipitation method as described above, washed and sensitized, their preparation is completed by incorporating commonly used photographic additives. I can do it. They can then be applied in photographic applications where silver and/or dye images are to be produced, such as conventional black-and-white photography or solid-state photography.

Research Disclosure, Volume 176, December 1978, Item 17643 e V, M*■t X
As described in Sections mX, ■ and X4, the emulsions prepared by the method of the invention may contain fluorescent brighteners, anticapri agents, stabilizers, scattering or absorbing materials, depending on the photographic application.
A hardening agent, a coating aid, a plasticizer, a lubricant, and a dissipating agent can be added.Addition, coating, and drying methods as described in Sections X and X7 of the same document can be adopted. . It can be prepared using a commonly used photographic support as described in Section X1. The photographic element may be a black-and-white photographic element or a color photographic element, with the latter being preferred. Reference 4, supra, forms silver and/or dye images by removal or physical removal. Particularly preferred color photographic elements use color developers and dye-forming cazolers to form dye images. In use, the photographic element is exposed as described in Section X1, supra, and processed as described in Section XEK.

(d) Specific examples of implementation In the following, the present invention will be further described with reference to examples and application examples. In all examples, the term "%" means a weight value unless otherwise specified.

The term rMJ used in the examples means the limit υmole unless otherwise specified.Furthermore, all solutions are aqueous solutions unless otherwise specified.In addition, in any preparation, the process of introducing silver and halide salts The contents were stirred vigorously.

Example 1 1.5% gelatin solution containing 0.17M potassium bromide5.
511, 2M potassium bromide and 2.0M potassium bromide by double jet method at 80°C
Silver nitrate solution was added over 2 minutes. During this time pBr t
0.8 (0.56 of the total amount of silver nitrate used)
The addition of the potassium solution was stopped and the addition of the silver nitrate solution was continued for 3 minutes (consuming 5.52% of the total silver nitrate used).

Potassium bromide and silver nitrate solutions were added simultaneously over a period of 13 minutes while maintaining part t-1,0 and accelerating the flow rate (flow rate at the end was 2.2 times that at the beginning) (
34.8 of the total amount of silver nitrate used was consumed). Stop the addition of the potassium bromide solution and add 1 t of silver nitrate solution for 1.7 minutes (consuming 6.44 of the total silver nitrate used);
Potassium iodide 0.24Mt - containing potassium bromide 1.8
While accelerating the flow rate with the M solution and total silver nitrate solution (9) double-) method, the flow rate at completion is 1.6 times that at the start! 90 pBr added over 715.5 minutes is 1.6
(consumed 45.9% of the total silver nitrate used). Addition of both solutions was stopped and sodium thiocyanate was aged for 5 minutes using x, s, 17 mol Ag. Potassium iodide solution o, i sM and silver nitrate solution at equal flow rates pa
Addition was made by the Dagurget method until r reached 2.9 (consuming 6.8 g of the total silver nitrate used). Total about 1
Emulsion 1 using 1 mol of silver nitrate was cooled to 30°C,
Cleaning was performed by the coagulation method described in US Pat. No. 2,614,929.

Example 2 1.5% gelatin solution containing 0.17M potassium bromide5.
2.1 M of potassium bromide and 2.0 M of silver nitrate solution were added to 51 at 80° C. and pH 5.9 over 2 minutes by the Dazorget method while stirring. pBr maintained at 0.8 (consumed 0.53% of total silver nitrate used)
, stop adding the potassium bromide solution and add the silver nitrate solution to the tube 4.6.
The addition continued for minutes (8.6% of the total silver nitrate used was consumed). Potassium bromide solution and silver nitrate solution were then added simultaneously for 13 minutes.

During this time, the pBr was maintained at 1.2, and the addition flow rate was accelerated so that the completion time was 2.5 times that at the beginning (consumed 43.6% of the total silver nitrate used). Addition of potassium bromide solution was stopped and silver nitrate solution was added for 1 minute (consumed 4.7% of the total silver nitrate used).

Potassium bromide containing 0.30M't of potassium iodide2.
The 0M solution was added over 13.3 minutes along with the silver nitrate solution. Sodium thiocyanate was added to this emulsion, maintaining the pBr at 1.7 for 4 hours and accelerating the flow rate to 1.5 times the starting amount on completion (consuming 35.9 g of the total silver nitrate used). Added L591 mole Agt and held for 25 minutes. Potassium iodide solution 0.35M and steel nitrate solution were added at equal flow rates by double jet method for about 5 minutes until pBr reached 3.0 (about 6.6M of the total silver nitrate used was consumed). The amount of total silver nitrate consumed was about 11 moles. A solution of phthalated gelatin 35 M'' dissolved in 1.21 ml of water was added, the emulsion was cooled to 30° C. and washed according to the coagulation method of Example 6. The emulsion was then subjected to spectral sensitization and chemical sensitization in the same manner as Emulsion I. Phthalated gelatin was used in U.S. Pat.
．． No. 614,929.

Example 3 0.8 Tigelatin solution containing 0.10M potassium bromide 30
Add double di solution 1.2 to 01 with stirring at 75 °C.
M was added for 5 minutes, during which time the pBr was reduced to 1. OK
(2,1- of all silver nitrate used was consumed).

Then a solution containing 17.6% phthalated gelatin5.
Added Ol and held the emulsion for t-1 minute. Then added until pBr reached 1.35 (consumed 5.24% of the total silver nitrate used). Potassium iodide 0
．． A 1.06 M potassium bromide solution containing 14M was added along with a silver nitrate solution at an accelerated flow rate (double the flow rate at the beginning) according to the 1c da Purge method. During this time, the pBr was maintained at 1.35 (9% of the total silver nitrate used).
2.7%), the total amount of silver nitrate used was approx.
As in Example 1, the emulsion was cooled to 35° C. and coagulated and washed.

Example 4 1.8 M of potassium bromide and 2.0 M of silver nitrate were added to 4.5 l of a gelatin 1.5-solution containing 0.17 M of potassium bromide at 55° C. and pH 5.6 with stirring by double jet method. Equal flow rates were added over a period of 1 minute while maintaining the pBr at 0.8 (consuming 0.7 s of the total silver nitrate used). Potassium bromide, silver nitrate and potassium iodide 0.26M solutions were added simultaneously in equal flow over a period of 7 minutes while maintaining a pBrt of 0.8 (consuming 4.8% of the total nitrate steel used). .

This triple addition was then carried out at an accelerated flow rate (completion flow rate was 4 times the starting rate) for an additional 37 minutes while maintaining the pBr at 0.8 (consuming 94.5% of the total silver nitrate used). ), the total amount of silver nitrate used was approximately 5 moles. Cool the emulsion to 35°C and add 200 g of phthalated gelatin.
Water containing 1. O1 was added and the emulsion was coagulated and washed in the same manner as in Example 1.

% 5 (This emulsion was prepared by a procedure similar to that described in U.S. Pat. No. 4,184,877) Gelatin 5
Aqueous solution 17.51 of ammonium iodide and silver nitrate 4.7M were added at constant and equal flow rates over 3 minutes using the double jet method while stirring 17.51 hours of aqueous solution at 65°C.During this period, the pI was 2.1 (consumed approximately 22% of the silver nitrate used in seed particle preparation). Next, the flow rates of both port liquids were adjusted to a flow rate sufficient to consume about 78 g of the total silver nitrate used for seed particle preparation, and addition was carried out for 15 minutes. Then, the addition of ammonium iodide solution was stopped and the addition of silver nitrate solution was stopped until the pI was 5.
．． The total amount of silver nitrate used in the preparation of type 0 particles was about 56 moles. The emulsion was cooled to 30° C., and the average grain diameter of type 0 grains used as a seed grain emulsion was 0.2 to prepare further emulsions as described below.
It was 4' micrometers.

A 5% gelatin solution containing 4.1 moles of AgI emulsion prepared as described above was heated to 65°C. A 4.7 M ammonium bromide solution and a 4.7 M silver nitrate solution were added at constant and equal flow rates over a period of 7.1 minutes using the DaPurge method. During this time, the pBr was maintained at 4.7 (40.2S of the total silver nitrate used for preparing the seed particles was consumed). Then, the addition of only the ammonium bromide solution was continued, and the addition was stopped when the pBr reached about 0.09.
It was held for 0 minutes.

The pH was adjusted to 5.0 using sulfuric acid, and the addition of both ammonium bromide and nitric acid chain solutions was carried out again for 14 minutes. The par was maintained at approximately 0.9 during this time (56.8% of the total silver nitrate was consumed). The pBr was then adjusted to 3.3 and the emulsion was cooled to 30°C. The total amount of silver nitrate used was about 87 moles. 900g phthalated gelatin
was added to coagulate and wash the emulsion.

(This emulsion is described in U.S. Pat. No. 3,320,069 and is of type 9) Potassium bromide 0.050M, Potassium iodide 0.012
Solution containing M and potassium thiocyanate 0°051M1 4,2. OJl! (phthalated gelatin 1, 25
% of potassium bromide and 1.43 Mt of silver nitrate solution were added to this solution over a period of about 40 minutes with stirring at 1.32 M of potassium bromide and 1.43 M of silver nitrate containing 0.11 M of potassium iodide. 21 moles of silver nitrate were consumed by precipitation formation.

Then, the emulsion tube was cooled to 35°C, and the emulsion tube was cooled to 35°C.
Coagulation and cleaning was performed according to the method described in , No. 928.

(The type described in the margin below) Potassium bromide 0.050M, potassium iodide 0.012
42.0 IC of a solution containing 0.051 M of potassium thiocyanate and 68
A potassium bromide solution 1 containing 0.053M of potassium bromide was added to it by a double jet method while stirring at ℃.
．． Add 37M and 148M silver nitrate solution at a flow rate of m over about 40 minutes9. This was due to precipitation formation.

Margin below jjl,.

fjKIKIK Example Emulsions 1 to 4 are tabular grain emulsions with a specified height and asquite ratio. In these emulsions and in the examples described below, some tabular grains with a diameter of less than 0.6 micrometers were included when calculating the average diameter of the tabular grains and the projected area. Except as otherwise noted, small amounts of small diameter tabular grains were present which did not materially affect the stated numbers.

The average grain diameter and average grain thickness were compared to determine the typical average asquite ratio of the comparative emulsion grains. Although not measured, the projected area of a few tabular grains meeting the criteria of less than 0.3 micrometers in thickness and at least 0.6 micrometers in diameter was assessed by visual inspection in each case; Even if such grains were present, they accounted for a very small portion of the total projected area of the total grains in the comparative emulsion.

Example 8 24% phthalated gelatin solution 4.55! -5,8,7
Potassium bromide was added at 1°C to bring the pBr to 1.3, and while stirring, 1.4% of potassium bromide containing 0.088M potassium iodide was added using the double jet method.
0M solution and 1.46M solution of nitrate steel at pBr of 1.3
The solution was added for 27 minutes while maintaining the temperature. Approximately 4.6 moles of silver nitrate were consumed. The emulsion was cooled to 50° C. and held for 15 minutes in the presence of 8.9y1 mole Ag of sodium thiocyanate.
It was coagulated and washed according to the method described in No. 28. In addition,
In this example as well as in other examples, the contents of the reactor were vigorously stirred during the process of adding silver salts and halide salts.

A micrograph of the prepared emulsion is shown in FIG.

The average diameter of the tabular grains was 1.25 micrometers, and the average thickness was 0.07 micrometers. The average aspect ratio of the tabular grains was 18:l.

The tabular grains accounted for 72% of the total projected area of the silver halide grains. The silver halide grains that were precipitated consisted of silver iodobromide (containing iodide! 6 moles).

Example 9 Phthalated gelatin 2.27% solution containing 0.060M sodium bromide 22! With stirring at 70° C., a 0.97 M solution of potassium bromide (IJ) and a 1.0 M solution of silver nitrate containing 0.027 M of potassium bromide were added at constant and equal flow rates by the double-jet method to a pBr of 1.0 M while stirring at 70°C.
2 (consumed 1.6% of the total silver nitrate used).

Dapuljet addition continued for an additional 5.5 minutes while maintaining the pBr at 1.2 (consuming 4.5% of the gold/silver used). Stop adding sodium iodide and add 0.
4. a 3.88M solution of sodium bromide containing 12M;
0M silver nitrate solution to reduce the pBr to 1 for 95 minutes.
．． 2 and accelerating the flow rate (completion flow rate was 4.8 times the starting flow rate) (consumed 90.8% of the gold/silver used). A 0.40M solution of silver nitrate was then added until the pBr reached 3.4 (consuming about 3% of the total steel used).

The total amount of silver used was approximately 37 moles.

The emulsion was then coagulated and washed as in Example 8.

From the electron micrograph, this emulsion has an average grain diameter of Q, 9.
It was found to consist of tabular silver iodobromide grains having an average thickness of 41 m'L, about 0.07 ttm, and containing 3 moles of iodide. The average aspect ratio of the tabular silver iodobromide grains was 13:1, and they occupied 73 inches of the total projected area. FIG. 2 is a micrograph of the emulsion prepared in this example.

Example 10 Bromide Power IJ Bone gelatin 15 t (based on gelatin) solution containing uA (0.17 mol) (Solution A) 2.2
At 80°C and pBro 77, 2.19 mol of potassium bromide (CV) aqueous H (solution B-
1) and a 2.0 molar aqueous solution of steel nitrate (solution C-1) were added simultaneously at a constant flow rate over a period of 2 minutes (consuming 0.61 g of total silver nitrate).

At the end of the initial 2 minutes, the addition of solution B-1 was stopped, but solution C-1 was continued to be added until the pBr reached 1.00 at 80°C (2.44% of the total silver nitrate used). consumed). Next, a 2° aqueous solution of phthalated gelatin containing 0.10 mol of potassium bromide (solution D) was added.
47 was added at pBr 1.0.80'C. Then, solutions B-1 and C-1 were added into the reactor by the double jet method over a period of 24 minutes at an accelerated flow rate (flow rate at completion was 4.0 times that at the beginning) (total silver nitrate). 4
4 chi was consumed). After 24 minutes, the addition of solution B-1 was stopped, but solution c-1 went, "cr oi tepBr is 1.
．． Additions continued until reaching 80.

Solution C-1 and an aqueous solution (solution B-2) containing 217 mol of potassium bromide and 0.03 mol of potassium iodide were then heated into the reactor by a double jet method while the flow rate was accelerated (the flow rate was started at completion). ) 12
(consumed 50.4% of total silver nitrate).

Aqueous solution containing 0.3 mol of potassium iodide (solution B-3)
and an aqueous solution of 2.0 mol of silver nitrate (solution C-29) was added at a constant flow rate by double jet method until pBr reached 2.16 at 80'C (2.0 mol of total silver nitrate used).
(59% consumed). The amount of silver nitrate used in preparing this emulsion was 657 moles.

The emulsion was then cooled to 35°C and phthalated gelatin 13
．． 3. Add 0.3 OA of solution (based on gelatin);
It was coagulated and washed twice.

The average grain diameter of the obtained tabular grain silver iodobromide emulsion was 1 d.
5.0 μm, and the average particle thickness was about 0.11 μm.

The tabular grains accounted for about 90 inches of the total grain projected area and had an average aspect ratio of about 45:1.

Example 11 A tabular grain silver iodobromide emulsion (3Ml of iodide) was prepared as follows.

1.5% gelatin solution containing 0.17M potassium bromide 3.0! While stirring at 60° C., a 3% gelatin solution containing 4.34 M of potassium bromide and 4.0 M of silver nitrate were added.
The 0M solution was added by double jet method for 2.5 minutes.

During this time the pBr was maintained at 0.8 (4.8% of the total silver nitrate used was consumed). Then, the addition of the potassium bromide solution was stopped and the silver nitrate solution was added until the pBr reached 1.3.
for 1.8 minutes (consuming 43 grams of silver nitrate). Then, a 6% gelatin solution containing 4.0 M potassium bromide and 12 M potassium iodide was added (at a flow rate 2.0 times the starting rate at the same time as the silver nitrate solution). The pBr was maintained at 1.3' during this time (871 g of the total silver nitrate used was consumed). The potassium bromide solution addition was stopped and the silver nitrate solution was added over 1.6 minutes until the pBr reached 2.7 (consuming 3.8% of the total nitrate steel used). The emulsion was then cooled to 35° C. and phthalated gelatin 279Ii was added to 1.0 ml of distilled water. O! A solution dissolving the emulsion was added to coagulate and wash the emulsion. I got it.

The silver tribromide emulsion (3M% iodide) had an average grain diameter of about 1.0 μm, an average thickness of about 0.10 urr, an aspect ratio of about 10:1. The tabular grains accounted for 85 or more of the total projected surface area of the silver halide grains present in the emulsion layer.

Example 12 An emulsion was prepared as follows.

1.5 bone gelatin containing 0.17 moles of potassium bromide
% aqueous solution (solution A) with stirring at 5 V, 0.1 potassium bromide was added to it at pBr 077 for 2 minutes at the same constant flow rate by double jet method.
A 5 molar aqueous solution (solution B-1) and a 3.00 molar aqueous solution of silver nitrate (solution C-1) were added (0.95 g of total silver nitrate was consumed).

After a margin of 2 minutes, stop adding solution 11 and continue. Solution C-1 is 55
The addition was continued at a constant flow rate until the pBr reached 1.14 at 0.degree. Next, a 3.00 mol potassium bromide aqueous solution (solution B-2) and a 0.37 mol potassium bromide sand aqueous solution (solution B-3)
and bromic acid chain aqueous solution (solution gc-i) by triple jet method F) while maintaining par at 1.14 and accelerating the flow rate (flow rate at completion was 10 times that at the start) Solution C- 1 was consumed until it was completely consumed (it was used for about 34 minutes and 89.5% of the total amount of silver nitrate was consumed).
3.00 molar aqueous solution of silver nitrate (solution C-2) and solution B
-3 was added by double-jet method at a constant flow rate at 5°C until pBr reached 2.83 (consuming 9.53% of the total amount of glass used). The amount of silver nitrate used in preparing this emulsion was approximately 6.3 moles.

Emulsion 1 was cooled to 35°C and phthalated gelatin 18.1%
Add 90.901 water solution (based on gelatin weight), 2
Washed and coagulated.

Application examples of 1'':4 emulsions The usefulness of the high aspect ratio tabular grain silver iodobromide emulsions of the present invention will be understood from the following examples.

Sensitization Example 1 The green spectral sensitizer Anhydro-5 was added to the emulsion at 40°C.
-Chloro-9-ethyl-5'-phenyl-sodium salt 464# Add 1 mol Art, hold for 20 minutes, then pAg
It was adjusted to 1 to 8.4. To this emulsion were added 3.5 1 mol Ag of sodium thiosulfate pentahydrate and 1.5-1 mol Agt of tetrachlorosynthetic potassium. pAg 8.1
- then heated to 65°C for 5 minutes.

Examples 2.3 and 4 These emulsions were subjected to chemical sensitization and spectral sensitization in the same manner as the emulsion of Example 1. Example 5 (comparative example) The pAgi of the emulsion was adjusted to 8.8, and thiosulfate was added to the emulsion. 4.2 1 mol Ag of IJium pentahydrate and 0.6'Iv 1 mol Agt of tetra-Australian potassium were added. Then,
The emulsion was heated to 80°C for 16 minutes, cooled to 40°C, and treated with the green spectral sensitizer anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-.
3-(3-sulfopropyl);
387 μl of hydroxide sodium salt 1 mole Agt was added and the emulsion was held for 10 minutes. The chemical and spectral sensitization was optimal for the sensitizer used.

Example 6 (Comparative Example) The pAlt of the emulsion was adjusted to 8.1, and sodium periosulfate pentahydrate 5.0rr 191 mol Ag and tetrasynthetic potassium 2.OW#Ii 1 mol Agt were added to the emulsion. The emulsion was heat-finished at -65°C, cooled to 40°C, and the green spectral sensitizer anhydro-5-chloro-9-ethyl-5'-phenyl-3'' (3-sulfobutyl)-3
-(3-sulfopropyl)oxacarbocyanine hydroxide sodium salt 464 to 1 mol Ag? Add r,
The emulsion was then held for 10 minutes. This chemical and spectral sensitization was optimal for the sensitizer used. Example 7 (Comparative Example) The pAg of the emulsion was adjusted to 8.8 and 10191 moles of sodium thiosulfate pentahydrate was added to the emulsion. Ag and 2.0 Mg of tetra-Kinji potassium were added to 1 mole of Ag, then emulsion, 1
Finished by heating at -55°C, cooled to 40°C, [color spectral sensitizer anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3- 3,871,191 mole of cyanine hydroxide sodium salt was added and the emulsion was then held for 10 minutes. This chemical and spectral sensitization was optimal for the sensitizers used. Example 10 Anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3 -(3-sulfopropyl)oxacardacyanine hydroxide sodium salt 350 to 1 mol Agq anhydro-11-ethyl-
1,1'-bis(3-sulfopropyl)-naphtho[1,
2-d) Oxazolocal is cyanine hydroxide 10
1-1 mol A [sodium thiosulfate pentahydrate 61119
1 mol Ag and tetra synthetic potassium 3 da 1 mol Age
Spectral sensitization and chemical sensitization of emulsions were carried out using this method.

Explanation of photographic effects Sensitivity in dye images using the emulsions of Examples 1 to 4 above
Improvements in granularity relationships will be explained.

Cellulose triacetate films were coated separately on supports as single layer magenta compositions of chemically and spectrally sensitized emulsions. Each coated element is coated with a halodanized emulsion containing 1.07t/W of silver? , gelatin 2.141/rr? This emulsion contains in advance the following:
magenta grain-forming coupler 1-(2,4-dimethyl-6-
Chloro-phenyl)-3-[α-(3-n-J-ntadecylphenoxy)-butyramide]-5-pyrazolone 0.
75 no/ze, anti-fouling agent 5-m@e-octadecylhydroquinone-2-sulfonate potassium salt 3.2?1
Mol^g and anti-capri agent 4-hydroxy-6-methyl-1*3*3m+7-thitraadeindene 3.6/1
A solvent dispersion of molar Ag was added. Gelatin 0.
887-/? F! An overcoat layer containing 1.75% (based on gelatin weight) of the hardener bis(vinylsulfonylmethyl)ether and the hardener bis(vinylsulfonylmethyl)ether was formed.

The resulting nine photographic elements are θ~3.0 density stepped tablé.

600 W 30 for 1/100 seconds through a T + Wratten JI & 9 filter and a 1.26 density neutral filter
00' to a tungsten light source. Pritixi Akira Journal Op Photography Annual,
1979, pp. 204-206 at 37.7°C. The current time was changed to obtain a capri concentration of 0.10. Relative green sensitivity and RM8 for each photographic element
Granularity t - Measured 7'j (RM8 Granularity H, C, Shi & Kit (8ehmltt), Jr, and J, H
, Altman Applied Odetics, vol. 9, pp. 8'71-874.19703. It can be seen that the high aspect ratio silver iodobromide emulsions exhibit a significantly better sensitivity-granularity relationship than the low aspect ratio silver iodobromide emulsions 5, 6 and 7.

A single layer configuration in which all silver halide emulsions are coated with equal silver coverage and a common silver/coupler ratio eliminates complex interactions and provides a good view of the sensitivity-granularity relationship of the silver halide emulsions. It should be understood that this is the best configuration. In the following margin, the improvement in the sensitivity-granularity relationship of the silver film is shown using the emulsions of Examples 1 and 4.

Emulsion Examples 1 and 4 according to the present invention and Comparative Example Emulsion 5
, 6 and 7 were optimally chemically and spectrally sensitized as described above and coated onto a polyethylene terephthalate film support. Each coated element is coated with a silver halide emulsion at a silver coverage of 3.21.
9'/m'' and gelatin at a ratio of 4.1697-m, and these emulsions were previously added with an anti-capri agent 4-hydroxy-6-
Methyl-1,3,3m, guanato-2 azoindene3.
677/MokAg was added. Gelatin 0.889/
An overcoat layer containing 1.75 sachets (based on total gelatin content) of the hardener bis(vinylsulfonylmethyl) ether was formed.

The resulting photographic element was exposed to a tungsten light source at 600 W 3000 @ for 1/100 second using a θ ~ 3.0 density step tablet f Lasula, a ten cliff 9 filter and a 1.26 density neutral filter. Then the exposed elements are 2
It was developed with N-methyl-p-aminophenol sulfate hydroquinone (Koda, DK50) at 0°C.

The current time for the low aspect ratio grain emulsion was 5 minutes, and the current time for the high aspect ratio tabular grain emulsion was 3.5 minutes, and curve shapes that matched K)9 were obtained for comparison. The obtained sensitivity and granularity measurement results are shown in Figure 4 as log green sensitivity versus R.
The sensitivity-granularity relationship of comparative emulsions 5, 6 and 7, shown as a plot of M8 granularity (XIO), is clearly inferior compared to emulsions 6 and 9 according to the invention.

It is shown that the emulsion of Example 10 increases the sensitivity resolution between the spectral sensitization region and the original sensitivity region.

Four multicolor photographic elements (structures ■ to ■) were prepared.

The structures of these elements were substantially identical except for the differences described below.

The margin 0C below is the protective gelatin oat coat, and YF is 0
．． Yellow colloid scissors that can be coated at a rate of 69 g/m" and act as a yellow filter material. B, G and R are blue, green and red recording powers 2-
Represents a cambial layer unit, color cambial layer unit) B, G
i or R-17) The prefix T indicates that the emulsion layer comprises a high aspect ratio tabular grain silver iodobromide emulsion as described in more detail below. Color Forming Layer) B, Gf and R are preceded by at least one other color forming layer in which the photographic sensitivity of the color forming layer unit records an exposure of 1/3 of the same wavelength in the same layer arrangement. This shows that the sensitivity of the layer unit is much higher. color cambium)
A prefix of 98 before B+G or R indicates that the photographic sensitivity of the color forming layer unit is lower than the sensitivity of at least one other color forming layer unit recording exposures of the same chromatography of the same layer arrangement. The meaning 6IL means an interlayer containing scavenger but substantially free of yellow filter material. Blue color without the symbol T in front (B),
The green (G) and red (B) recording color forming layer units contained low aspect ratio silver bromide or silver bromide emulsions prepared according to the techniques taught in U.S. Pat. No. 3,320,069. . Corresponding layers in each structure have the same iodide content unless otherwise noted in %.

The fast tabular grain green sensitive emulsion layer contained the emulsion of Example 10 which was chemically and spectrally sensitized as described above.

The high-sensitivity tabular grain red-sensitive emulsion layer was optimally sensitized by the same method as the emulsion of Example 10 in 1.
Anhydro-5,6-dichlorol as a spectral sensitizer
-ethyl-3-(3-sulfobutyl)-3'-(3-sulfobutyl)benzimidazolonaphtho[1,2-d)-
Thiazolocal contains 144-1 mol kg of cyanine hydroxide and anhydro-5,5'-dichloro-3,9-
The only difference is that cyanine hydroxide was used for diethyl-3'-(3-sulfobutyl)-thiacal. Structure I
The fast green and red sensitive emulsion layers of structures 1 and 2 contained 9 moles of iodide, while the fast tabular grain green and red sensitive emulsions of structures 1 and 2! contained 1.5 molar and 1.2 molar of iodide, respectively.

For further details regarding other structures (1) to (2), please refer to US Pat. No. 4,184,876.

Structure ■~■ is 600W28 under the same conditions for 1/100 seconds through an O~4 density step tablet with daylight 5 filter and 0.20 steps! The light source was foggy at SO'. Also, use other sandals with structures 1 to ■ in the same way as above! However, a Roughten 98 filter was additionally interposed to obtain blue exposure. Additionally, other samples of Structures I to (3) were exposed in the same manner as above, but with the additional intervention of a Laughten 9 filter to obtain negative blue exposure. All samples were C
-41 color negative process under the same conditions. Genwei conducted the test at 38°C for 3 minutes and 15 seconds. Yellow, magenta and cyan characteristic curves were plotted for each sample. By matching these curves obtained from different samples to their minimum concentration levels ~
That is, a comparison was made by polymerizing the lowest concentration portion of the curve.

The results are summarized in Table n. Margin below ν
△ △A is the formula (
4), that is, ("W98 GW?8)-(BN-
GM) is the difference between the logarithm of the blue sensitivity of the blue recording color forming unit and the logarithm of the blue sensitivity of the green recording color forming unit.

B is the logarithm of the blue sensitivity of the blue recording color forming unit and the red recording color forming unit defined by the above formula (B), that is, ("wps-"!?8) (,BeeR,) This is the difference from the logarithm of blue sensitivity.

C is the door crusher 1 (
1 pass = OD, which is the difference between the logarithm of the color sensitivity and the logarithm of the blue sensitivity of the green recording color forming unit, is the difference between the logarithm of the blue sensitivity of the green recording color forming unit. It is the difference between the logarithm and the logarithm of the blue sensitivity of the red recording color forming unit.

Comparing the structure plate and the plate, it can be seen that excellent sensitivity resolution can be obtained in the case of the structure plate using the tabular grains. Depending on the structure, it is not possible to achieve excellent sensitivity resolution as in the case of structure 2, but since the structure uses a yellow filter material, the structure does not have the disadvantages associated with the use of yellow filter materials as in the case of Tsumugi. ■Photos related to the present invention!
Although containing more yellow filter material than would be necessary for normal use, structure 1 shows that the sensitivity resolution of the structure can be increased if desired by utilizing a small yellow filter concentration.

Monochrome photographic elements were prepared by coating the fast green sensitized tabular grain emulsion compositions described above onto a film support and overcoating with a gelatin protective layer. The blue to minus blue sensitivity resolution of this photographic element was then determined according to the exposure and processing techniques described above. The quantitative difference defined by the above equation (0, i.e., GW? - GW9g) was 1.281 og E. It shows that a suitable blue to minus blue degree sensitivity resolution can be achieved if the recording emulsion layer is placed close to the radiation source and no blue absorbing layer is placed above it.

Figure 3 illustrates sharpness improvement in multilayer photographic elements using emulsions obtained in accordance with the present invention.

Compare and contrast photographs in these examples demonstrating the improvement in image sharpness in photographic elements using several V scratches and 11 agents! 'Basically, U.S. Patent No. 3
A low-aquid ratio silver iodobromide emulsion of the type described in No. 320,069 was used. The low T ratio emulsion used here can be called a conventional emulsion, and its physical properties are shown in Table m below.

Table ■ CI 1.1. am 3: IC20,4-0,8Jm3: IC30,8μm 3:IC41,5μm 3:IC50,4-0,5#n3: IC60,4-0
, 8xm 3 :1 Four high ascent ratio 11 aspect ratio tabular grain silver iodobromide emulsions were prepared V@ according to a method similar to the Example emulsion.

The physical properties of these emulsions are shown in Table 2 below.

Table ■ Tabular grains Average grain thickness Average 7X-1/) Specific projected area Emulsion diameter Approximate diameter Approximate value
Occupancy rate (a) 2 T 4 1.6 μm Approx. 0.06 μm 27:
1 > 1 out of 70 Incisions were made in the same manner as in Examples 1 to 4.

Medium 2 PvIA was produced in the same manner as in Example 12 (the iodide content in the peripheral annular region of the tabular grains was rapidly increased).

Next, a coating layer of the above-mentioned iodide emulsions (CI-C6 and T1 to T4) was formed in a series of multilayer elements, and the variations of the Tomo 6M configuration are shown in the table along with the results. Although the emulsions were chemically and spectrally sensitized, sensitization is not necessary to achieve improved sharpness.

Common layer structure A Overcoat layer High sensitivity blue sensitivity Yellow dye forming layer Low sensitivity blue sensitivity Yellow dye forming layer Intermediate layer (single layer of yellow filter) High sensitivity green sensitivity 1 Zenta composite forming layer Intermediate layer High sensitivity red sensitivity Cyan Dye-Forming Layer Intermediate Layer Low Sensitivity Green Sensitive Magenta Dye Forming Layer Intermediate Layer Low Sensitivity Red Sensitive Cyan Dye Forming Layer Support Exposure and Processing Each sample was exposed and developed as follows. Sharpness was measured by measuring the modulation transfer function (MTF).

This method is described in Journal of Applied Photographic Engineering, Volume 6(1): 1-8.
, 1980.

Modulation transfer function r for red light and multilayer coating
Then, by calculating the light for 1/15 seconds at 601% modulation using a 29'Ij 0.7 intermediate dark filter, the light was calculated for 1/15 second. Measurement was performed by exposing for 1/15 second at 60 pixels using a green MTF Fi, Ten 99 filter. Processed by Briti.

Journal of Photography Annual, 1979. It was carried out according to the C-41 color negative process described in p. 204. My father-in-law and I are at 38℃ (100℃)
(lower) for 3.25 minutes. 1 from the MTF curve after a while
Cascade modulation transfer (CMT) acutance evaluation was performed at 6-magnification.

Results The composition of each coating layer and the CMT acutance values for red and green light are shown in Table VK below.

Dragon ■ 1 Structure A containing a conventional emulsion layer and a tabular grain emulsion layer
Sharpness coating layer (-xs) (#ts)
w) (Rumor) (Rumor) FY CI C
I T-I T-I T-I T-I T-IB
Y C2C2T-2T-2T-2T
-2T-2FM C3T-3T-3
T-3C3T-2T-2FCC4C4C4C4C4C4
T-2 8M C5T-4T-4C5C5C5
C58CC6C6C6C6C6C6C6 Red CMT Acutance 79.778.782,784.08
3.185.381153ΔCMT Uni, To... -1,0+3.0 +4.3
+3.4 +5fi +6fi Green CMT Acutance 86.587.893.192.89
0.192.8921ΔCMT Uni, To... +2.3 +6.6 +6
．． 3 +3.6 +63 +5fi1 As shown in Table V, sharpness can be reduced when tabular grain emulsions are used in one multilayer color coating layer.

Looking at the red CMT space, the sharpness of coating A2, which contains two tabular grain layers, is smaller (-1
, OCMT unit). Similarly, the sharpness of coating A3 with four tabular grain layers is greater than that of coating 44 with three tabular grain layers. The sharpness is low only in 0.4 CMT units and 45 units. However, for coatings A6 and A7,
Due to the proper placement of the specific tabular grain emulsion in a layer close to the radiation source (coating 46 has a red CMT clearance of 1.322, the sharpness is greater than that of coating A4). ), a significant sharpness improvement can be achieved compared to a control coating layer consisting entirely of conventional emulsions. As seen in the table above, coating A6 has a sharpness of 6.0 compared to coating A1.
3 green CMT units larger, coating plate 7 is sharper by 66 red CMT units compared to coating 41.

Structure B common to the following margins Overcoat layer High sensitivity Blue sensitivity Yellow composite forming layer Low sensitivity Blue sensitivity Yellow composite type layer Intermediate layer (Yellow fiber, Ruta single layer) High sensitivity Green sensitivity Magenta dye forming layer Low sensitivity Green-sensitive magenta color mark-forming layer Intermediate layer High-sensitivity red-sensitive cyan perforation-forming layer Low-sensitivity red-sensitive cyan color mark-forming layer Interlayer support coating It was exposed and processed in the same manner as in the specific example. The composition of the coating and the CMT acutance evaluation results are shown in Table V below.

Table ■ Structure A containing conventional emulsion layers and tabular grain emulsion layers
Sharpness coating layer of Al 2 3 4FY
CI CI T-I T
-IBY C2C2T-2T-2FM
C3T-3T-3035M
C5T-4T-4C'5FCC4C4C4C
4 5CC6C606C6 Red CMT Akinetance 80.0 78.4 83.9
82.8ΔCMT Uni, To... -1,6+3.9
+2.8 Green CMT Akinetance 87.3 88,9 94,3
92.3 From the data in Table 1 above, it can be seen that the sharpness of the photographic element is considerably improved by locating the tabular grains closest to the radiation source, and that the sharpness of the photographic element is significantly improved by placing the tabular grains closest to the radiation source, and that the tabular grain emulsion in the intermediate layer is It can be seen that the sharpness is more impaired by placing K below the emulsion layer.

Hereinafter, two types of monochrome elements (A:
Comparative Example B: Invention Example) was produced in p.

Table 1 C3T3 High-sensitivity magenta C5T4 Low-sensitivity magenta Next, the sharpness of the monochrome element was evaluated according to the same method as in the above specific example, and the following results were obtained.
Table below ■ A (comparative example) 93.9B (tabular grain emulsion) 97.3ii! The response to blue spectral sensitization using the emulsion of Example 11 is shown.

The emulsion was chemically sensitized using sodium thiocyanate, sodium thiosulfate and synthetic potassium tetrachloro.

Coating 1: A portion of a chemically sensitized emulsion was coated on a cellulose triacetate film support. The tabular copper iodobromide grain emulsion contained in this emulsion coating contains 1, 17- and 2.9-v gelatin, and is pre-contained with magenta dye-forming 1-(6-chloro). -2,4-dimethylphenyl)-3
-[α-(m-enttadecylphenoxy)butyramide)-5-pyrazolone (0,79 g/n”), 2-octadecyl-5-sulfohydroquinone (1,69,!i
'1 mole1 mole, and 4-hydroxy-6-methyl-
1, 3, 3m.

It contained 7-thitraadeindene (3,62F 1 mol Ag).

Coating 2: the second of the tabular grain silver bromide emulsion
5-anhydro-5,6-simethoxy5-methylthio-3,3'-di(3-sulfopropyl)thiocyanine hydroxide triethylamine salt (λgure
0nm) 3X10-' mol 1 mol A
Therefore, it was spectrally sensitized to blue light. Next, the same magenta dye-forming oak as in Coating 1 was added to the spectrally sensitized emulsion and coated in the same manner as above.

The coating layer is θ~3. Exposure was made to a tungsten light source at 1×25 seconds, 500 W, 5400' through an Os degree stepped tablet. Pretty, Shu Journal Ode Photography Annual.

1979, p. 204'-206 for 3 minutes.

Coating 2 is 0.421 compared to coating 1
It showed a higher photographic sensitivity by 0 gF. This shows that blue sensitization significantly increases the sensitivity.

The following is an example showing the characteristics of solid silver bromide having a uniform iodide distribution: Preparation of emulsion Emulsion 1 (Example) 4-O, SS bone gelatin aqueous solution containing 0,000 mol of potassium bromide 30. While stirring the OL well, 1.20 mol of potassium bromide and 1.2 mol of silver nitrate solution were added to it using a double jet method at a constant flow rate for 5 minutes at 75°C.
p&1. (2.40 of the gold and silver used)
% consumed). Phthalated gelatin solution (20%, 2.
4t) was added into the reactor and stirred at 75°C for 1 minute. The silver nitrate solution described above was then added at a constant flow rate at 75° C. over a period of about 5 minutes until a p& of 1.36 was reached (4.80 g of the gold/silver used was at own expense). An aqueous solution containing 1.06 mol of potassium bromide solution and 0.14 mol of potassium iodide and an aqueous solution of 1.2 mol of silver nitrate were prepared using the Mepuljet method while accelerating the Iff amount (the flow rate at the time of completion was changed from the flow rate at the start). The silver nitrate solution was increased by 2.4 times and added over a period of about 50 minutes until the silver nitrate solution was consumed. Temperature gold is 75℃ and pB
r was kept at 1.36 (consuming 92.8% of the total steel used, t), the amount of silver used in this emulsion preparation was approximately 20
It was a mole. After the precipitation was complete, the emulsion was cooled to 35°C, phthalated gelatin 350I was added, stirred well, and the emulsion was washed three times by the coagulation method described in US Pat. No. 2,614,929. Then bone gelatin 12.31 solution 2.
OL was added and the agent was adjusted to 5.5 and pAg to 8.3 at 40C.

The average tabular grain diameter of the resulting silver iodide (88:12) emulsion was 2.8 μm, the thickness was 0.095 μm, and the average aspect ratio was 29.5:1, and these tabular grains were present in the emulsion. It occupied more than 85% of the total projected area of the silver iodobromide particles.

Emulsion 2 (Example) (f containing 0.10 mol of potassium chloride) and 7.5 t of an 8% bone gelatin aqueous solution were mixed with 1.20 mol of potassium bromide and silver nitrate by the double jet method while stirring well. 1
．． 20 molar solution for 5 minutes at 65°C, p.
Br1. Added in Q (2.4% of total steel used)
). Phthalated gelatin solution (1-7,1,
After adding 0.7 t), the emulsion was stirred at 65° C. for 1 minute.・'-If you add a 1.20 molar solution of silver nitrate to a pBr of 1
．． Addition was made at 65° C. until 36 was reached (consuming 41 − of the total steel used).

A solution containing 1.06 mol of potassium bromide and 0.14 mol of potassium iodide and a solution of 1.20 mol of silver nitrate were heated by the double jet method while accelerating the flow rate (the flow rate at the end was twice that at the beginning). ) was added over a period of 52 minutes. The temperature was 65° C. and the pBr was maintained at 1.36 (93.5 − of the gold and silver used was consumed).

The amount of silver used in this emulsion preparation was approximately 5.0 moles. After the precipitation was completed, the emulsion was cooled to 35 DEG C., the temperature was adjusted to 3.7, and the emulsion was washed by the method described in US Pat. No. 2,614.92. Additional phthalated gelatin solution (17.6%, 0.5t) was added and after stirring for 5 minutes the emulsion was again cooled to 35°C at pH 4.1 and prepared as described in US Pat. No. 2,614,929. Washed according to method. Next, bone gelatin 11.
Add 0.7t of 4% solution, -55 of emulsion, 8.3
The temperature was adjusted to 40°C).

The average tabular grain diameter of the resulting silver iodobromide emulsion (88:12) was 2.2 μm, the thickness was 0.11 μm, and the average as
The contrast ratio was 20:1, and the tabular 4-+j particles accounted for more than 85-+ of the total projected area of the silver bromide grains present in the emulsion.

11. Agent 3 (Example) Contains 0.10 mol of potassium bromide. , 8- While thoroughly stirring 7.5 tons of bone gelatin aqueous solution, 1.2 moles of potassium cybromide and 1.5 tons of silver nitrate were added to it by the double jet method.
20 molar solution at a constant flow rate for 5 minutes at 55°C, p.
Added at Br 1.0 (used 9 gold and silver 2.40
− was consumed)゛. Phthalated gelatin aqueous solution (17,1
After stirring at 55°C for 1 minute, a 1.20 molar solution of silver nitrate was added at a constant flow rate until pBr reached 1.36 (using 9: 4.1 t of silver was consumed). did). A solution containing 1.06 mol of potassium bromide and 0.14 mol of potassium nitrate and a 1.20 mol solution of copper nitrate were prepared using a double jet method while accelerating the flow rate (the flow rate at the end was changed to 55°C at the start). The pBr was maintained at 1.36 (93.591 of the gold and silver used was consumed).
4m1! The amount of silver used was approximately 5.0 moles. After the completion of precipitation, the emulsion was cooled to 35°C, and - was adjusted to 3.7.
Cleaning was performed by the method described in US Pat. No. 2,614,929. Additional phthalated gelatin solution (17,6
%, 0.5t) and after stirring for 5 minutes, the emulsion was again cooled to 35°C at pH 4.1 and
14,929, and then added 0.7 t of bone gelatin aqueous solution (11,411G) to adjust - to 5.5 and pO to 8.3 at 40°C.

The resulting silver iodobromide (88:12) emulsion had an average tabular grain diameter of 1.7 μm and a thickness of 0.117111? , the average aspect ratio is 15.5:1, and the tabular grains occupy 851s of the total projected area of the silver iodobromide emulsion present in the emulsion.
It accounted for more than that.

Emulsion 4 (Example) 1.20 mole of potassium bromide and 1 silver nitrate were added to a 0.8-timber bone gelatin aqueous solution Nf7.51 containing 0.10 mole of potassium bromide by the Daprenoet method while stirring well.
．． 55 molar solution for 2.5 minutes at a constant flow rate.
℃, pBr 1.0 (20% of the gold/silver used)
．． 40- was consumed). Phthalated gelatin aqueous solution (17
, 111,0,74) and stirred for 1 minute at 55°C, 1.20 mol of silver nitrate solution was added at a constant flow rate until pBr reached 1.36 (4.1- of the total scissors used were consumed). ), potassium bromide 1.06 mol and potassium hundredthide 0
．． A solution containing 14 moles of nitric acid #2.0 moles was added over a period of 52 minutes using the double jet method at an accelerated flow rate (the flow rate at completion was twice that at the beginning). . The temperature was 55°C and the pBr was maintained at 1.36 (
It consumed 93.5- of nine gold and silver. The amount of silver used in preparing this emulsion was approximately 5.0 moles. After precipitation, the emulsion was cooled to 35 DEG C., adjusted to -3.7 and washed according to the method described in U.S. Pat. No. 2,614,929. Additional heptalized gelatin solution (17,
6%, 0.5t) and the emulsion was heated at 40°C, pi-16.0.
It was redispersed at After stirring for 5 minutes, the emulsion was adjusted to pH 4,
1, cooled again to 35°C, and US Bit patent No. 2.6
It was washed according to the method described in No. t 4.9'z e. Next, 0.7 t of bone gelatin 11.4-aqueous solution was added, and at 40°C, the emulsion was 5.51 and the ceramic was 8.3.
It was adjusted to

The resulting silver bromide (8,8:12) emulsion had an average tabular grain diameter of 0.8 μm and a thickness of 0.08 μm, an average aspect ratio of 10:1, and ose-like grains in the emulsion. It accounted for more than 5591 of the total projection surface particles of copper bromide particles present in the area.

Emulsion A (comparative example) Potassium bromide 0.045 mol, potassium iodide 0.01
'! - Heptalated zetutin 1.0791 aqueous solution containing 0.11 mol of sodium thiocyanate 9, Ot
Place in a precipitate-forming reactor and stir.9.

The temperature was adjusted to 60°C. A 1.46 molar solution of potassium bromide containing 0.147 mol of potassium bromide and 1.67 mol of silver nitrate were poured into this reactor by the double jet process.
The molar solution was added at a constant flow rate over 40 minutes at 60°C, consuming 4.0 moles of silver.

The reaction was completed in 1 minute and the addition of the halide salt solution was stopped. After forming the precipitate, the emulsion was cooled to 33°C and washed twice according to the coagulation method described in US Pat. No. 2,614,929. Next, add Bone Zella F71 6.5% solution 68011/ to bring the emulsion to -6.
Adjusted to 4.

Emulsion B (comparative example) An emulsion was prepared in the same manner as in Emulsion A above.

However, the temperature was reduced to 50° C. and the total reaction time was reduced to 20 minutes.

Emulsion C (comparative example) An emulsion was prepared in the same manner as in Emulsion A.

However, the temperature was reduced to 50℃, and the total reaction
reduced in minutes.

Emulsion D (comparative example) The emulsion was cracked in the same manner as in Emulsion A above.

However, the temperature was increased to 75°C. The total reaction time was 40 minutes.

Table of tabular grains and comparative silver iodobromide
Skin 1 Tabular 2.8μs 0.095μm 29.
5:1 >B52 Flat plate 2.2μm 0.1
111m 20:1 >853 Flat plate 1.
7μm 0.11μm l 5.5: 1>
8! S4 flat plate 08μ beak 0.08 voice m
10:1 >55A spherical 0.994m * >
1:1 Umbrella wheel B Spherical 0.89μm Umbrella Yo1:1 Sachi*C Spherical 0.91μN@*
Yu 1:1*Medium D Spherical 1.10Jm
Umbrella ==1:l *Considered to be approximately equal to the diameter of the particles in the car *In fact, there were qualitatively no tabular particles larger than 0.6 microns in diameter.

Emulsions 1 to 4 and each of Kai to D are bromide 88
It contained 12 moles of iodide. In each emulsion, the iodide is substantially uniformly dispersed within the grains.

The B1 dye imaging tabular grain and control AzBrl emulsions were optimally chemically sensitized at 40° C. and PAN 8.25 according to the conditions described for coatings below. The tabular grain emulsions were spectrally sensitized at 40'C1 pAg 9.95 prior to chemical sensitization, whereas the control emulsions were optimally spectrally sensitized without further p~ adjustment after chemical sensitization. Sensitized. The amounts of sensitizers in the table below are all #1 mole Ag. Table ■ 1 3.0 9.0 100 5'6
0'C70024,012,01000'60C793
34,012,01000'65℃ 5OO45,0
15,01005'60C900 Hayabusa gloss A A 1.0 2.9 0 5'6
5℃ 210B 1.1 3.2
0 5'65℃ 290c O, 82,
465′e5℃ 233D O,51,50
5'65℃ 200*Potassium chloroaurate sulfur-sodium thiosulfate pentahydrate Thiocyanate Sodium thiocyanate**Color 311
Differences in sensitization conditions when anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3-(3-sulfobutyl)oxide requires cyanine hydroxide sodium salt However, this difference was necessary to achieve optimal sensitization for each different emulsion. If the control emulsions were chemically and spectrally sensitized in the same manner as the tabular grain emulsions, their relative properties would be inferior to the results described above. In order to subject the tabular grains and the control emulsion to the same sensitization and to discuss the results, a portion of Emulsion 2 and a portion of Emulsion C (respectively Emulsion 2!) were used.
and emulsion Cx) were taken out and subjected to chemical sensitization and spectral sensitization as described below. Each emulsion has a dye of 900 x 1
Spectral sensitization was carried out using molar silver at 40°C, p~9.95, pAg was adjusted to 8.2 at 40°C, then tetrachlorosynthetic potassium 40-1 mol ~, sodium thiosulfate pentahydrate 12 ．． Chemical sensitization was carried out for 20 minutes at 65 DEG C. using .theta.

AgBr1, O71/- and Gelatin 2.15 platelet-like grains and control AgBr1 emulsions separately as single layer magenta configurations on cellulose triacetate film supports.
It was coated in a ratio of I/-.

This coating element contains magenta monomer-forming Kagler 1-(2,4-//methyl-6-chloro4-ethyl)-3
-(α(3-n-<ntadecylphenoxy)-butyramide]-S- & lazolone o, 75I/-, anti-capri agent 4-hydroxy-6-methyl-1*3t3ae7-titraadeindene Φ sodium salt 3 .6111 mol Ag
and a solvent dispersion containing 3.5117 mol or more of potassium 5-octadecylhydroquinone-2-sulfonate as a stain inhibitor. This coating layer was overcoated with a 1,5117 m'' layer of gelatin and hardened with 1.5-bis(vinylsulfonylmethyl)ether based on total gelatin content.

The above coating is graded at a concentration of 0 to 3.0.

600W for 1/100 second through a Toglaslater flat 9 filter and a 1.8# neutral filter.

Exposure to a tungsten light source at 3000°. 1.5 minutes to 6 minutes at 37.7°C using the Tung color developer described in Petit Tissue Journal Op 07 Otography Annual, 1979.204-206.
Developing was performed for different times between minutes to obtain a balanced capri level. Both relative sensitivity and granularity measurements were made independently on Capri at 0.25 density units. Figure 14 shows log green sensitivity vs. RM8 granularity (XI
O). As shown in the figure, the tabular grain AgBrI emulsion exhibited an excellent sensitivity-granularity relationship compared to the control emulsion.

! 1('), the sensitivity-granularity relationship of Emulsions 2x and Cx should be compared. When the tabular grain and control emulsions 2r and Cx are subjected to identical chemical and spectral sensitization, the sensitivity-granularity relationship of emulsion 2x is much better than that of emulsion Cx. This is quite surprising. This is the right thing to do.
Emulsion 2! and CI have an average volume of 0.418 μml and 0.394 μml per particle, respectively. *- and are substantially the same.

To compare the relative degradation in negative blue and back sensitivity of the invention and control emulsions, the emulsions sensitized and coated as described above were tested in 0 to 3.0 density steps (0,1511 degree steps). Plus 2. Ten 43.6
The dorsal region of the screen was exposed by a tungsten light source at 600 W, 3000° for 1/100 seconds through a +38a74 router and a 1.0 density neutral filter.

Negative blue exposure was performed in the same manner. However, uh, tenmu 3
6+38a] was replaced with a Futten 49 filter, and a 1.8 concentration 22 filter was used as the neutral filter. Pritish Journal Op Photography Annual 1979.

204-206 at 37.7 DEG C. for a period of time ranging from 1.5 to 6 minutes. Sensitivity/Capri is gross.

Relative blue and minus blue sensitivities were listed in 0.209 degree units on Toshi and Capri. The sensitivity measurement results are shown in Table W below.

Table MV flat plate l +45 umbrella 2 +42 3 +43 4 +37 Comparative example A -5 B +5 C+.

D -5 *30 relative sensitivity unit so 0.30Logi E above table X ■
As shown in Table 1, the tabular grain Ag Br l emulsion exhibited a significantly greater negative blue-color sensitivity separation compared to the control emulsion with the same halide composition. These results indicate that an optimally sensitized high aspect ratio emulsion Specific tabular grain Ag
BrI emulsions are generally optimally sensitized conventional Ag Br emulsions.
The Il emulsion exhibits increased sensitivity in the black and white region. If the iodide-containing background is reduced, the resolution of the negative blue and background sensitivity increases considerably, as already explained in the previous example.

Emulsions 1.2 and 3 and comparative emulsions A, B.

The sharpness of C and D was compared. Sensitization, coating and processing were performed as described above. U-Ten A99
6 for filters (1/30 to 1/2 in l modulation)
The modulation transfer function for green light was obtained by exposing the coating for an appropriate time between seconds. After processing, the above M
Cascade modulation transmission (
□) Performed an acutance evaluation. The green CMT'accumulation of the invention example emulsions was 98.6 to 93.5. The line color O-light acutance of the comparative emulsion is 93.1.
It was ~97.6. The results are shown in Table XVK below, comparing the texture and color of Emulsions 2 and C, which had substantially similar average capacity per grain.

Table x Green G-Acutance Invention Example Emulsion 2 97.2 Comparative Control Emulsion C
96, I CO silver image formation at 40°C - of the control emulsion -6.2, pAg of 8
．． The emulsion was chemically sensitized optimally using IJium pentahydrate and tetrachlorosynthetic potassium at D0, and the emulsion was maintained at a predetermined density for a certain period of time.

A predetermined amount of anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3 was added to this emulsion.
- (3-x Ruho fr1 building) - Oxacal? , cyanine hydroxide (dye A) and anhydro-3-ethyl-9-methyl-3'-(3-sulfozotyl) thorium cyanine hydroxide (dye B) were added. Sensitized nine (see table below for details)
Please refer to ).

The tabular grain emulsion was spectrally sensitized by adding colored grains A and B to the emulsion at 40° C. and PAN 9.95, and then sensitized using sodium thiocyanate, sodium thiosulfate pentahydrate, and Tetrac-synthetic potassium. It was chemically sensitized at a certain temperature for a predetermined period of time (see instructions below).

Table x ■ 1 100/45/1.5 0/60 387/23
6 10132 1QO/4s/13 5/60
387/236 101.53 100/4.5/1
．． 5 5/60 581/354 100B4 1
00/12/4 0155 58v354 g7
3A O/1.9410.97 5/65 123
/ 77 97.6B O/1.9410.97
15/65 139/ 88 g65CO/1-9
410.97 10/f15 116/73 g7
．． 5D O/1. ! 'to10.525 5/60
68.1/ 43 98.0*8 CN: Sodium thiocyanate 8: Lithium thiosulfate pentahydrate Au: Tetrachloro Synthetic potassium emulsion is coated on a film support with silver 4.3 #/j and gelatin 7
．． It was coated at a ratio of 5311/-. All coating layers were hardened using mucochloric acid (1,0, gelatin). 0.0% leaf gelatin in each coating. s
91/-〇O79- coat was applied.

The method for obtaining the photographic modulation transfer function is described in Journal of Applied Photography, Co. Engineering, 6 (
1):1-8.1980.

1 in 60-modulation using 12 neutral density filters
The modulation transfer function was determined by exposure for /Is seconds.

2 using N-methyl-p-aminophenol nalphate-hydroquinone developer (Koda, developer-76@).
It was treated for 6 minutes at 0°C. 3 from Genshi's successor Makyokushin
Cascade modulation transfer (CM1') clearance was evaluated in 5-arm amplification (see Table XM above).
.

It can be seen from the data in Table xv1 above that sharpness is clearly improved when tabular grain emulsions are applied in black and white configurations.

To round out the comparison of the sensitivity-granularity relationship, separate sections of the coating layer described above were exposed to a tungsten light source at 600 W, 5500° for 1/100 seconds through an O ~ 4.0 continuous density doublet and N-methyl- Incubation was carried out at 20° C. for 4.6 and 8 minutes using a paraphenol sulfate hydroquinone present agent (i-Dac present agent D-76). Relative sensitivity values were measured at 0.30 density units on Capri and RMEI parallel light (green) granularity was measured at 0.6 density units on Capri.

Figure 6 shows the log sensitivity versus semi-parallel light granularity obtained after 6 minutes of development, as shown in Figure 6. The sensitivity-granularity relationship of the emulsion is excellent compared to the AgBrI control emulsion. Current time 4 minutes and 8
Similar results were obtained for minutes. Matching contrast was not obtained in these examples, with the tabular grain emulsions exhibiting higher contrast. This indicates that high contrast tabular grain emulsions have higher granularity than would be achieved if the contrast of the emulsions were balanced. Therefore, Figure 15 shows that the tabular grain emulsion is clearly superior to the control emulsion in that it exhibits higher contrast than the control emulsion; The complete sensitivity-granularity relationship is not shown.

Example illustrating the characteristics of an emulsion with an American 4-total ratio (175:1). , 156μ and average aspect ratio of 175
: Showed 1. The tabular grains accounted for 95 or more of the total projected area of the silver iodobromide grains.

Sodium thiocyanate (1501191 mol Ag),
anhydro-5,5-dichloro-3,3'-bis(3-
The emulsion was prepared at 65° C. in the presence of sidotriethyl aine salt (850y1 mol Ag), sodium thiosulfate pentahydrate (1,5091 mol At) and tetrachlorotetrasynthetic potassium (0.75W 1 mol Ag) in thiacyanine hydrochloride (sulfoirovir). Chemical sensitization and spectral sensitization were performed by holding for 10 minutes at .

Yellow-forming Kagler α-piparyl α-(4-(4-human tetraxybenzene-sulfonyl)) was added to the sensitized emulsion.
ytnyl]-2-chloro-5-(n-hexadecanesulfonamide)-acetanilide (0,911/rn"
), 4-hydroxy-6-methyl-1t3#31#7
-Chitraadeindene (3,7N1 mol fine), 2-(2
-octadecyl)-5-sulfohydroquinone sodium salt (3,4111 mol Ag) was added and deposited on a polyester film support with 1.351/- of silver and 2.5% of gelatin.
It was coated at a ratio of 58jF/-. In this emulsion layer, bis(vinylsulfonylmethyl)ether
.

Gelatin layer containing 1.0- (0,541/m”)
O/Der coat.

The dried coating layer was passed through a gradient density step wedge equipped with a 1.0 neutral density filter Plusra, Ten 2B filter at 500 W at 1/100 sec.

5500c1 light source, The Pritish Journal of Photography Annual, 197
9, pp. 204-206 for 4.5 minutes at 37.8°C.

Dmin' of this element is 0.13, Dm■X is 1.45
, the conotraft was 0°56.

Margin below (@) Effects of the invention According to the method of the invention, silver iodobromide grains in an emulsion having a reduced thickness and a high aspect ratio compared to emulsions hitherto obtained in the photographic field are produced. A radiation-sensitive silver iodobromide emulsion consisting of silver iodobromide grains and a dispersion medium, which account for a high proportion of the total grain projected area, can be advantageously 'Vll[.

In the four-body application example of the above-mentioned water, the sensitivity of the high aspect ratio tabular grain silver iodide emulsion according to the present invention - granularity of 1, sharpness, !color sensitivity, !color sensitivity and minus 1 color sensitivity It shows the advantages regarding the difference between

The high aspect ratio tabular grain emulsion obtained in the present invention enhances the sharpness of emulsion 1- which is placed at the bottom when in practice it is placed to receive light without scattering. In this regard, the emulsion obtained according to the invention is a radiation source KIIk4 emulsion' (I
This is especially effective when K is installed.

When the emulsion obtained according to the present invention is subjected to spectral tl sensitization at a wavelength other than the W color region of the spectral sensitization, the emulsion has a large sensitivity resolution in the heavy color region of the spectral region compared to the region of the spectrum to be spectral sensitized. The color sensitized silver iodobromide emulsions of the present invention exhibiting a 5 minus! color sensitization are much less sensitive to backlight as compared to minus color growing light, and therefore are less sensitive to light such as daylight at !5500'. The silver iodobromide emulsion obtained by the present invention, when sensitized, does not require retention of the filter to produce an acceptable negative W color exposure record when exposed to a single beam of light. Compared to grain emulsions, TE generally exhibits an even further increased sensitivity-granularity relationship compared to the previously achieved sensitivity-granularity relationship of silver iodobromide emulsions. If there is, the original 1vf!!,
Compared to the sensitivity, the blue sensitivity of the silver iodobromide emulsion contemplated by the present invention is significantly increased.

The preferred emulsion obtained in the present invention, which has a higher iodide concentration in the transversely displaced regions compared to the central region, is a conventional silver iodobromide emulsion or a hitherto known low aspect ratio tabular grain iodobromide emulsion. Compared to emulsions, an increased speed-granularity factor (e.g., higher speed at comparable granularity or reduced granularity at comparable speed) can be achieved; These preferred high aspect ratio tabular grain iodobromide emulsions produced by the present invention are superior in resistance and other photographic properties compared to non-tabular core/sheath emulsions having comparable surface iodide concentrations. The emulsion produced is spectral sensitized to produce a dye pre-form, and is therefore very effective during storage. These preferred emulsions of the present invention have been shown to unexpectedly increase dye yield when used with color developers and dye-forming graphics.

The emulsion obtained by the present invention can be used as a radiolucent support! !
Cross-over can be advantageously controlled when used in surface-coated radiographic elements.Comparing a radiographic element using an emulsion according to the invention with a similar radiographic element using a conventional emulsion. It becomes clear that crossover can be reduced by the emulsion of the present invention. Alternatively, emulsions according to the present invention may be used to achieve comparable cross-over-sea levels with lower silver ranges.

The transfer film unit containing the emulsion obtained in the present invention has a large ratio of IE sensitivity to that before silver coating (i.e., t of silver halide coated per unit area), and it is possible to obtain a visible transfer film more quickly. This makes it possible to obtain transfers with greater contrast in a shorter development time.

The silver iodobromide emulsions obtained in this invention further exhibit advantageous photographic properties such as reduced sensitivity to processing temperature variations, increased color contrast and increased image quality.

Furthermore, advantages in photographic properties depending on each photographic application field can be obtained.

The method of the present invention provides an advantageous method for producing high aspect ratio silver iodobromide emulsions. Although the use of seed crystals is possible in the practice of the present invention, it is also possible to provide seed crystals to obtain grains with high aspect ratios, as well as to improve the settling conditions between the cough formation and the growth stages of emulsion precipitation. It is also unnecessary to control the

In a preferred form, the precipitation force method of the present invention uses conventional tabular silver iodobromide grains 1IlIIj! Compared to other methods, this method is advantageous in that it is simpler to produce, and also provides a high aquidity ratio tabular grain three-silver bromide emulsion that could not be obtained using other methods.

[Brief explanation of drawings]

Figures 1 and 2 are micrographs 1i-1 of the emulsion prepared by the method of the present invention. ii′! Figures 3, 4, 5 and 6 show the relationship between emulsion sensitivity and granularity. Patent Applicant Eastman Koda, Ri Kanno Patent Agent Patent Attorney Akira Miyagi Patent Attorney Kazuyuki Nishidate Patent Attorney 1) Yukio Patent Attorney Akira Yamaguchi FIG, / IG 2 'I Yangya Iya ka Seal

Claims (1)

[Claims] 1. Prepare a radiation-sensitive silver iodobromide emulsion consisting of a dispersion medium and silver iodobromide grains by introducing a complex salt, a bromide salt, and an iodide salt into a reactor containing at least a part of a dispersion medium. In the method, the dispersion medium in the reactor before introducing the iodide salt is adjusted to a par') of 0.6 to 1.6, and the dispersion medium in the reactor before introducing the complex salt and the bromide salt is substantially iodized. In the process of introducing iodide salt, the pBr in the reactor is kept at least 0.6.
and thus maintain a thickness of 0 in the dispersion medium in the reactor.
Iodobromide steel particles having a diameter of less than 3 micrometers, a diameter of 0.6 micrometers or more, an average aspect ratio of greater than 8:1, and occupying at least 50 mm of the total projected area of the iodobromide steel particles. A method for preparing a high aquidity ratio tabular grain silver iodide emulsion, which is characterized by producing silver grains.